3-i 

CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT 

 

TABLE OF CONTENTS 

3.1 INTRODUCTION ........................................................................................................... 3-1

3.2 SCOPE ............................................................................................................................. 3-1

3.2.1 Definitions............................................................................................................ 3-1

3.2.1.1 High-Intensity Discharge Lamp ............................................................... 3-1

3.2.1.2 Mercury Vapor Lamp .............................................................................. 3-2

3.2.1.3 Metal Halide Lamp .................................................................................. 3-2

3.2.1.4 High-Pressure Sodium Lamp ................................................................... 3-2

3.2.2 Scope .................................................................................................................... 3-3

3.2.2.1 Wattage .................................................................................................... 3-3

3.2.2.2 Correlated Color Temperature ................................................................. 3-4

3.2.2.3 Directional Lamps .................................................................................... 3-4

3.2.2.4 Self-Ballasted Lamps ............................................................................... 3-5

3.2.2.5 Lamps Operated on Electronic Ballasts Only .......................................... 3-5

3.2.2.6 High-CRI Lamps ...................................................................................... 3-6

3.2.2.7 Colored MH Lamps ................................................................................. 3-7

3.2.2.8 MV Lamps for Specialty Applications .................................................... 3-8

3.2.2.9 Electrodeless HID Lamps ........................................................................ 3-8

3.2.2.10 Summary ............................................................................................. 3-9

3.3 MARKET ASSESSMENT .............................................................................................. 3-9

3.3.1 Trade Associations ............................................................................................... 3-9

3.3.2 Manufacturers and Market Share ....................................................................... 3-10

3.3.3 Small Businesses ................................................................................................ 3-11

3.3.4 Regulatory Programs ......................................................................................... 3-11

3.3.4.1 Federal Energy Conservation Standards ................................................ 3-11

3.3.4.2 California Energy Commission.............................................................. 3-12

3.3.4.3 Canadian Energy Efficiency Standards ................................................. 3-14

3.3.4.4 European Energy Efficiency Regulations .............................................. 3-14

3.3.5 Non-Regulatory Initiatives................................................................................. 3-17

3.3.5.1 Federal Energy Management Program .................................................. 3-17

3.3.5.2 ENERGY STAR .................................................................................... 3-18

3.3.5.3 Energy Efficient Commercial Building Deduction ................................ 3-19

3.3.5.4 Efficiency Vermont ................................................................................ 3-20

3.3.5.5 Pacific Gas and Electric ......................................................................... 3-20

3.3.5.6 San Diego Gas and Electric Company ................................................... 3-21

3.3.5.7 Omaha Public Power District................................................................. 3-22

3.3.5.8 Lyon-Lincoln Electric Cooperative, Inc. ............................................... 3-23

3.3.5.9 North Carolina Municipal Power Agency 1 .......................................... 3-23

3.3.6 Historical Shipments .......................................................................................... 3-23

3.4 TECHNOLOGY ASSESSMENT .................................................................................. 3-27

3.4.1 Basic Structure and Operation of HID Lamps ................................................... 3-27

3.4.2 Mercury Vapor Lamps ....................................................................................... 3-29
3-ii

3.4.2.1 Lamp Construction................................................................................. 3-29

3.4.2.2 Lamp Operation ..................................................................................... 3-31

3.4.3 High-Pressure Sodium Lamps ........................................................................... 3-33

3.4.3.1 Lamp Construction................................................................................. 3-33

3.4.3.2 Lamp Operation ..................................................................................... 3-35

3.4.4 Metal Halide Lamps ........................................................................................... 3-38

3.4.4.1 Lamp Construction................................................................................. 3-38

3.4.4.2 Lamp Operation ..................................................................................... 3-46

3.4.5 HID Ballasts ....................................................................................................... 3-47

3.4.5.1 Magnetic Ballasts ................................................................................... 3-47

3.4.5.2 Electronic Ballasts ................................................................................. 3-50

3.4.6 HID Fixtures ...................................................................................................... 3-52

3.4.7 HID Lamp Technology Options ........................................................................ 3-52

3.4.7.1 Mercury Vapor ....................................................................................... 3-52

3.4.7.2 High-Pressure Sodium ........................................................................... 3-53

3.4.7.3 Metal Halide........................................................................................... 3-53

3.5 EQUIPMENT CLASSES .............................................................................................. 3-54

3.5.1 Correlated Color Temperature ........................................................................... 3-54

3.5.2 Wattage .............................................................................................................. 3-55

3.5.3 Bulb Finish ......................................................................................................... 3-56

3.5.4 Luminaire Characteristic .................................................................................... 3-57

3.5.5 Bulb Shape ......................................................................................................... 3-59

3.5.6 Base Type........................................................................................................... 3-60

3.5.7 Lamp Operating Orientation .............................................................................. 3-60

3.5.8 Equipment Class Summary ................................................................................ 3-61

REFERENCES .......................................................................................................................... 3-62

LIST OF TABLES 

Table 3.3.1 CEC Standards for MH Luminaires Manufactured Before January 1, 2009 .......... 3-12

Table 3.3.2 Canadian Proposed Standards for HID Lamp Ballasts ........................................... 3-14

Table 3.3.3 Minimum Efficacy EU Requirements for HPS Lamps with a Color Rendering Index 

(Ra) ≤ 60 (Second Stage) ........................................................................................................... 3-15

Table 3.3.4 Lumen Maintenance and Lamp Survival Factors for HPS Lamps (Second Stage) 3-15

Table 3.3.5 Minimum Efficacy EU Requirements for MH Lamps with Ra ≤ 60 and for HPS 

Lamps with Ra > 60 (Second Stage) ......................................................................................... 3-16

Table 3.3.6 Minimum Efficacy EU Requirements for other HID Lamps (Second Stage) ........ 3-16

Table 3.3.7 Minimum Efficacy EU Requirements for MH Lamps (Third Stage) ..................... 3-16

Table 3.3.8 Lumen Maintenance and Lamp Survival Factors for MH Lamps (Third Stage).... 3-16

Table 3.3.9 FEMP Efficiency Requirements for Federal Purchases ......................................... 3-18

Table 3.3.10 ENERGY STAR Residential and Commercial Directional Luminaire Requirements

.................................................................................................................................................... 3-19

Table 3.3.11 ENERGY STAR Residential Non-Directional Luminaire Requirements ............ 3-19

Table 3.3.12 PG&E HID Lamp and Fixture Rebates (2013-2014) ........................................... 3-21

Table 3.3.13 SDG&E HID Lamp and Fixture Rebates ............................................................. 3-22

Table 3.3.14 OPPD 2013 Retrofit and Replacement Incentives ................................................ 3-23
3-iii

Table 3.3.15 Historical Shipments of HID Lamps .................................................................... 3-27

Table 3.4.1 Building Blocks of an HID Ballast and Associated Characteristics ....................... 3-51

Table 3.5.1 Equipment Class Divisions Based on CCT ............................................................ 3-55

Table 3.5.2 Equipment Class Divisions Based on Wattage ....................................................... 3-56

Table 3.5.3 Equipment Class Divisions Based on Bulb Finish ................................................. 3-57

Table 3.5.4 Equipment Class Divisions Based on Luminaire Characteristic ............................ 3-59

Table 3.5.5 HID Lamps Interim Analysis Equipment Classes .................................................. 3-61

LIST OF FIGURES

Figure 3.3.1 Shipments of HID Lamps ...................................................................................... 3-24

Figure 3.3.2 HID Lamp Market Share by Lamp Type .............................................................. 3-25

Figure 3.3.3 2010 HID Lamp Market Share .............................................................................. 3-26

Figure 3.4.1 Light Emission Process of an HID Lamp .............................................................. 3-29

Figure 3.4.2 Mercury Vapor Lamp Construction ...................................................................... 3-30

Figure 3.4.3 Mercury Vapor Spectral Power Distributions ....................................................... 3-32

Figure 3.4.4 High-Pressure Sodium Lamp Construction ........................................................... 3-34

Figure 3.4.5 Cross Section of a Typical Seal Assembly for an HPS Lamp with a Ceramic Arc 

Tube ........................................................................................................................................... 3-35

Figure 3.4.6 High-Pressure Sodium Spectral Power Distributions ........................................... 3-37

Figure 3.4.7 Operation Limits for 400 W HPS Lamp................................................................ 3-38

Figure 3.4.8 Metal Halide Lamp Construction .......................................................................... 3-39

Figure 3.4.9 Common Configurations for Horizontal Metal Halide Lamps.............................. 3-40

Figure 3.4.10 Common MH Arc Tubes: (a) Ovoid, (b) Pinched Body ..................................... 3-41

Figure 3.4.11 CMH Lamp Arc Tube Design ............................................................................ 3-42

Figure 3.4.12 Metal Halide Lamp Arc Tube Designs ................................................................ 3-43

Figure 3.4.13 Metal Halide Spectral Power Distributions ......................................................... 3-47

Figure 3.4.14 Core and Coil Assembly of a Magnetic Ballast .................................................. 3-48

Figure 3.4.15 Electronic HID Ballast ........................................................................................ 3-50

Figure 3.4.16 Electronic HID Ballast Block Diagram ............................................................... 3-50
3-1 

CHAPTER 3.MARKET AND TECHNOLOGY ASSESSMENT 

3.1 INTRODUCTION 

This chapter consists of four sections: scope, the market assessment, the technology 

assessment, and equipment classes. The scope describes the categories of HID lamps that would 

be subject to the energy conservation standards under consideration in this rulemaking. The 

market assessment provides an overall picture of the market for the equipment concerned, 

including the nature of the equipment, industry structure, and manufacturer market shares; 

regulatory and non-regulatory efficiency improvement programs; and market trends and 

quantities of equipment sold. The technology assessment identifies a list of technologies to 

consider in the screening analysis. The equipment classes section discusses the equipment 

classes DOE is considering for this rulemaking and how they were developed. 

The information DOE gathers from the market and technology assessment serves as 

resource material for use throughout the rulemaking. DOE considers both quantitative and 

qualitative information from publicly available sources and interested parties. 

3.2 SCOPE 

This section puts forth the statutory definitions that define the scope of this rulemaking 

and conducts a close review of specific lamp types to determine the HID lamp types for which 

DOE will consider energy conservation standards in this rulemaking. DOE considered each of 

these specific lamp categories according to the criteria prescribed by EPCAenergy savings 

potential, technological feasibility, and economic justification. (42 U.S.C. 6295(o)(2)(A)) 

DOE assessed a lamp category’s potential for energy savings using lamp catalog data as a 

proxy for market share, which was then reevaluated in light of feedback obtained during 

manufacturer interviews. For HID lamp availability, DOE obtained quantitative information 

from lamp catalogs of 14 different manufacturers. DOE also conducted evaluations of 

technological feasibility and economic justification. 

3.2.1 Definitions 

The Code of Federal Regulations (CFR) currently defines HID, mercury vapor (MV), and 

metal halide (MH) lamps. The following sections describe in more detail the definitions in the 

CFR and those that were proposed in the HID lamps final determination and test procedure 

Notice of Proposed Rulemaking (NOPR). 

3.2.1.1 High-Intensity Discharge Lamp 

The CFR defines HID lamp (10 CFR 431.282) as follows: 

High-intensity discharge lamp means an electric-discharge lamp in which— 

(1) The light-producing arc is stabilized by the arc tube wall temperature; and 
3-2 

(2) The arc tube wall loading is in excess of 3 Watts/cm2

High-intensity discharge lamps include mercury vapor, metal halide, and high-pressure 

sodium lamps. 

3.2.1.2 Mercury Vapor Lamp 

The CFR currently defines MV lamp, but the HID lamp test procedure NOPRbproposes a 

revised definition as follows: 

Mercury vapor lamp means a high-intensity discharge lamp, including clear, phosphorcoated, and self-ballasted screw base lamps, in which the major portion of the light is produced 

by radiation from mercury typically operating at a partial vapor pressure in excess of 100,000 Paa

(approximately 1 atm). 

The CFR also defines specialty application mercury vapor lamp ballast (10 CFR 431.282) 

as follows: 

Specialty application mercury vapor lamp ballast means a mercury vapor lamp ballast 

that— 

(1) Is designed and marketed for operation of mercury vapor lamps used in quality 

inspection, industrial processing, or scientific use, including fluorescent microscopy and 

ultraviolet curing; and 

(2) In the case of a specialty application mercury vapor lamp ballast, the label of which— 

(i) Provides that the specialty application mercury vapor lamp ballast is ‘For specialty 

applications only, not for general illumination’; and 

(ii) Specifies the specific applications for which the ballast is designed. 

3.2.1.3 Metal Halide Lamp 

The CFR currently defines MH lamp, but the HID lamp test procedure NOPRbproposes a 

revised definition as follows: 

Metal halide lamp is a high-intensity discharge lamp in which the major portion of the 

light is produced by radiation of metal halides and their products of dissociation, possibly in 

combination with metallic vapors. (42 U.S.C. 6291(63)) 

3.2.1.4 High-Pressure Sodium Lamp 

The CFR does currently not define HPS lamp. However, the HID lamp final 

determination and test procedure NOPRbproposed to adopt the ANSI C82.9-1996 definition of 

HPS lamp: 

 

a

 Atm, Pa, and Torr are all units of pressure. atm is the abbreviation for atmosphere. Pa is the abbreviation for 

pascal. 760 Torr = 1 atm. 1 Torr = 133 Pa. 

b

 The HID lamp test procedure NOPR was issued by DOE on December 15, 2011 and is available at: 

http://www1.eere.energy.gov/buildings/appliance_standards/rulemaking.aspx/ruleid/21. 
3-3 

High-pressure sodium lamp is a high-intensity discharge lamp in which the major portion 

of the light is produced by radiation from sodium vapor operating at a partial pressure of about 

6,670 pascals (approximately 0.066 atm or 50 Torr) or greater. (76 FR 77914, 77317, Dec. 15, 

2011) 

3.2.2 Scope 

HID lamps can differ from each other due to a variety of characteristics that affect 

performance, such as input wattage, directionality, ballast location, ballast type, color of emitted 

light, and others. The following subsections provide a discussion of these features and describe 

the lamps that DOE is considering for standards in this rulemaking. 

3.2.2.1 Wattage 

In examining manufacturer catalogs, DOE found that HID lamps span wattages from 15 

watts (W) to 18,000 W, though these wattages varied according to lamp technology. Rated 

wattages range from 15 W to 18,000 W for MH lamps, from 35 W to 1000 W for HPS lamps, 

and from 40 W to 2000 W for MV lamps. DOE is considering standards for a subset of the 

available wattages, as explained in the following paragraphs. 

For MH lamps, DOE is considering standards for lamps with rated wattages ≥50 W and 

≤2000 W. Based on entries in manufacturer catalogs, less than nine percent of MH lamps 

available have rated wattages less than 50 W. DOE found less than three percent of MH lamps to 

have rated wattages that exceed 2000 W. The small number of HID lamp offerings at low 

wattages does not suggest significant potential energy savings. Similarly, at high wattages, the 

small number of available lamp models and their low operating hours provides limited energy 

savings potential. Conversely, between 50 W and 2000 W, as described in chapter 5 of the 

interim technical support document (TSD), DOE has identified a range of efficacies and design 

options available for MH lamps, indicating technological feasibility for standards. DOE also 

preliminarily determined that standards could be economically justified. For these reasons, DOE 

is considering energy conservation standards for MH lamps with rated wattages ≥50 W and 

≤2000 W. This is consistent with the preliminary approach in the energy conservation standards 

rulemaking for metal halide lamp fixtures (MHLFs).c

For HPS and MV lamps, DOE is considering standards for lamps with rated wattages ≥50 

W and ≤1000 W. In its review of HPS and MV lamp catalogs, DOE found that less than five 

percent of the HPS catalog offerings and less than one percent of the MV catalog offerings had 

rated wattages less than 50 W. Similarly, DOE found only two MV lamps and no HPS lamps 

with rated wattages higher than 1000 W. Given the small number of available products, DOE 

believes these lamps do not reflect significant potential energy savings. Therefore, DOE is 

considering standards only for those HPS and MV lamps with rated wattages ≥50 W and ≤1000 

W. HID lamps in the wattage ranges included in the analysis, named above, have demonstrated 

the potential for significant energy savings. These lamps also have a range of efficacies and 

 

c

 The metal halide lamp fixture preliminary TSD is available at: 

www.eere.energy.gov/buildings/appliance_standards/commercial/metal_halide_fixtures_prelim_tsd.html. 
3-4 

design options, which suggest technological feasibility, and DOE preliminarily determined that

standards could be economically justified. 

3.2.2.2 Correlated Color Temperature 

Another defining characteristic of an HID lamp is the correlated color temperature (CCT). In 

general terms, the CCT is an approximation of the appearance of the light source expressed in 

kelvins (K) where lower values are considered warm white light and high values are considered 

cool white light. In the test procedure NOPR, DOE proposed to define CCT as the absolute 

temperature of a blackbody whose chromaticity most nearly resembles that of the light source. 

(42 U.S.C. 6291(30)(K)); (76 FR 77914,77930, Dec. 15, 2011). 

HID lamps are available with a variety of CCTs, depending on lamp type and design. For 

example, HPS lamps range in CCT from 1900 K to 2700 K, and MV lamps range in CCT from 

3200 K to 6800 K. In reviewing HID lamp catalogs, however, DOE found a much larger range 

for MH lamps, with products ranging in CCT from 2800 K to 50,000 K.d

DOE found that lamps with higher CCTs tend to be advertised for a specific, specialized 

application. For example, DOE found that all MH lamps with a CCT between 10,000 K and 

50,000 K were advertised as aquarium lamps, and MH lamps with a CCT between 7200 K and 

9000 K were advertised as stage and studio lighting. In addition, DOE identified lamps with a 

CCT of 7000 K to be horticulture lamps. 

 

Overall, lamps with a CCT greater than or equal to 7000 K represent about two percent of 

all available MH lamp models, based on catalog availability. Given the small number of 

available products and their specialized applications, DOE does not believe these lamps 

represent significant potential energy savings. Therefore, DOE is not considering energy 

conservation standards for high-CCT lamps (with a CCT ≥7000 K). 

In summary, DOE is considering standards for the following CCT ranges in this 

rulemaking: HPS lamps ≥1900 K and ≤2700 K, MV lamps ≥3200 K and ≤6800 K, and MH 

lamps ≥2800 K and <7000 K. Lamp catalogs show a large number of lamp offerings in these 

ranges, suggesting the potential for significant energy savings and the technological feasibility of 

such savings, and preliminary results suggest that energy conservation standards for these lamps 

could be economically justified. 

3.2.2.3 Directional Lamps 

Lamp light distribution is typically categorized as omni-directional or directional. Omnidirectional lamps emit light in all directions with approximately equal intensity, whereas 

directional lamps use a secondary optical element (e.g., reflector, lens, refractor, light guide) or a 

combination of elements to shape the light distribution into a particular pattern. In the test 

procedure NOPR, DOE proposed “directional lamp” be defined as a lamp emitting at least 80 

percent light output within a solid angle of π (pi) steradians (corresponding to a cone with an 

angle of 120 degrees) (76 FR 77914, 77917, Dec. 15, 2011). 

 

d

 Some directional MH lamps are available with a CCT as low as 2500 K. 
3-5 

DOE found that manufacturers offer both directional and omni-directional lamps for each 

of the three HID lamp types. By analyzing manufacturer catalogs, DOE found that less than 10 

percent of available HID lamps are directional. Lamp manufacturers noted during interviews, 

however, that the actual market share of directional HID lamps is much smaller than their catalog 

representation indicates. Because each directional lamp provides a specific beam pattern, a larger 

number of directional lamp offerings are needed to meet all customer needs. Manufacturers 

indicated that this fact belies their low shipment volume relative to their representation in 

catalogs. Given their small market share, DOE does not believe directional lamps represent 

significant energy savings potential. Furthermore, the pattern of light distribution of these lamps 

makes them unacceptable replacements for omni-directional lamps. Therefore, DOE is not 

considering energy conservation standards for directional lamps. 

3.2.2.4 Self-Ballasted Lamps 

HID lamps can be also categorized by their ballast location (i.e., externally ballasted or 

self-ballasted lamps). The vast majority of HID lamps are operated with an external ballast, 

meaning that the ballast is not located within the lamp body (socket and envelope). An external 

ballast can be located within the fixture or installed separately from the fixture (e.g., at the base 

of a pole-mounted fixture). DOE refers to a ballast that is integrated into the lamp, however, as a 

self-ballasted HID lamp. In the test procedure NOPR, DOE proposed to define “self-ballasted 

lamp” as a lamp unit that incorporates all elements that are necessary for the starting and stable 

operation of the lamp in a permanent enclosure, and that does not include any replaceable or 

interchangeable parts (76 FR 77914, 77918, Dec. 15, 2011). 

A survey of the market revealed that MH and MV lamp types are available in selfballasted models, but HPS lamps are not. In reviewing catalogs, DOE found that less than one 

percent of MH lamps are self-ballasted, whereas about 17 percent of MV lamps are selfballasted. Of these self-ballasted lamps, most are also directional and would thereby be excluded 

from the scope. Many of the remaining omni-directional, self-ballasted lamps, which span a 

range from 100 W to 750 W, are marketed as replacements for incandescent technology. MV 

lamps have increased efficacy and longer lifetimes relative to incandescent lamps. However, 

DOE does not believe that regulating self-ballasted HID lamps would result in significant energy 

savings. Instead, adoption of energy conservation standards could increase the price of these 

lamps or eliminate them altogether, thereby shifting the market towards less efficient, 

incandescent lamps. Given the small number of available self-ballasted HID lamps and the 

expectation that customers would likely choose incandescent technology if self-ballasted HID 

lamps were regulated, DOE does not believe there is significant potential for energy savings by 

regulating these lamps. Therefore, DOE is not considering standards for self-ballasted lamps in

this rulemaking. 

3.2.2.5 Lamps Operated on Electronic Ballasts Only 

In its market research, DOE found that catalogs indicated that some HID lamps could be 

operated only by an electronic ballast. DOE conducted additional research on these lamps and

found that they tend to be newer models with uncommon rated wattages. Furthermore, DOE 

discovered that the reason that such lamps are reported for use with an electronic-ballast only 
3-6 

stems from American National Standards Institute (ANSI) lamp datasheets. ANSI provides 

specifications for operating HID lamps with magnetic ballasts only, regardless of whether a lamp 

can operate on an electronic ballast as well. When a manufacturer develops a new lamp with a 

rated wattage that is already included in ANSI C78.43-2007eor ANSI C78.44-2008fstandards, 

the lamp will be compatible with the magnetic ballast specifications reported on the ANSI 

datasheets. For a lamp with a new rated wattage to be added to the ANSI datasheets, however, 

ANSI requires that (1) at least two manufacturers independently produce a lamp model at the 

new wattage and (2) they, along with an ANSI committee, agree on the standardized operating 

specifications. In a situation where a manufacturer is the sole producer of a lamp with an unlisted 

wattage, the manufacturer often conducts research and development only for electronic operation 

of that lamp, leading to the designation of electronic-ballast only. In the framework document, 

DOE did not consider standards for these lamp types, primarily because of the absence of 

industry consensus test methods. These lamps also represent a small market share (less than one 

percent) based on feedback during manufacturer interviews. Therefore, for the interim analysis, 

DOE is not considering energy conservation standards for HID lamps marketed for exclusive use 

with electronic ballasts. 

3.2.2.6 High-CRI Lamps 

CRI is the measure of the degree of color shift objects undergo when illuminated by a 

light source as compared with the color of those same objects when illuminated by a reference 

source of comparable color temperature. (42 U.S.C. 6291(30)(J)) CRI ranges from zero for 

monochromatic light sources to 100 for a light source that closely mimics the color rendering 

properties of the reference source. HID lamps are available over a range of CRIs depending on 

the type, application, and environment in which the lamp is intended to operate. 

During manufacturer interviews, DOE learned that some manufacturers offer an HPS 

lamp with a higher CRI (60 or greater) than typical HPS lamps (a typical CRI value for HPS 

lamps is about 20). These high-CRI HPS lamps are generally marketed as an inexpensive way to 

achieve whiter, higher-CRI light than traditional HPS lamps, though increased color rendering is 

achieved at the expense of lamp efficacy. Instead of purchasing a new lamp, ballast, and fixture, 

the customer can use the high-CRI HPS lamp with their existing HPS ballast and fixture. 

According to HID lamp manufacturers, the market share of such lamps is extremely small—less 

than one percent of total industry HPS lamp shipments. For these reasons, DOE believes that 

high-CRI lamps do not have potential for significant energy savings. 

However, if DOE did not establish standards for these lamps but established a minimum 

efficacy standard for HPS lamps that would exceed the efficacy of high-CRI HPS lamps, there is 

the possibility that the market could shift to the unregulated, high-CRI HPS lamps. While high-

 

e

 ANSI C78.43-2007 American National Standard for Electric Lamps—Single-Ended Metal Halide Lamps is a 

standard published by ANSI that sets forth the physical and electrical requirements for single-ended metal halide 

lamps operated on 60 Hz ballasts to ensure interchangeability and safety and is available for download at: 

http://webstore.ansi.org/RecordDetail.aspx?sku=NEMA+ANSI+ANSLG+C78.43:2007

f

 ANSI C78.44-2008 American National Standard for Electric Lamps—Double-Ended Metal Halide Lamps is a 

standard published by ANSI that sets forth the physical and electrical requirements for double-ended metal halide 

lamps operated on 60 Hz ballasts to ensure interchangeability and safety and is available for download at: 

http://webstore.ansi.org/RecordDetail.aspx?sku=NEMA+ANSI+ANSLG+C78.44:2008
3-7 

CRI HPS lamps would provide reduced light output for a given wattage, customers may prefer 

the high-CRI HPS lamps due to the possibility of the unregulated lamp being offered at a lower 

cost (relative to a standard-compliant, traditional HPS lamp) and their compatibility with existing 

HPS ballasts and fixtures. Because alternative high-CRI lamp technologies exist in the wattage 

and CCT ranges under consideration, and to ensure the realization of energy savings associated 

with any adopted standards, DOE is considering standards for these high-CRI HPS lamps in this 

interim analysis. 

DOE observed a similar, but different trend regarding high-CRI MH lamps. MH lamps 

are available with CRI values up to 100, though a typical value for a pulse-start quartz MH lamp 

is about 65. The highest CRI MH lamps, those with CRI values greater than or equal to 95, 

utilize pulse-start (quartz and ceramic) technology. These high-CRI pulse-start MH lamps are 

predominantly offered by one company (over 80 percent of product offerings for pulse-start MH 

lamps with CRI values ≥95), indicating that these products are intended for a low volume, niche 

market. For this reason, DOE believes that high-CRI pulse-start MH lamps do not have potential 

for significant energy savings. 

DOE notes that pulse-start MH lamps with CRI values ≥95 often exhibit lower efficacy 

than other pulse-start MH lamps. If DOE did not establish standards for these lamps but 

established a minimum efficacy standard for MH lamps that exceeded the efficacy of high-CRI 

pulse-start MH lamps, it is unlikely that the market would shift to the unregulated, high-CRI 

pulse-start MH lamps. High-CRI pulse-start MH lamps are not likely to be a low cost substitute 

for standards-compliant lamps, because a high-CRI MH lamp is not currently a cost-saving 

option. Furthermore, for certain standard levels, transitioning to a high-CRI pulse-start lamp 

could require a purchase of a new pulse-start ballast and fixture. Because of their small market 

share and limited potential for energy savings, DOE is not considering standards for pulse-start 

MH lamps with CRI values ≥95 in this interim analysis. 

3.2.2.7 Colored MH Lamps 

DOE found a small number of HID lamps within the covered CCT ranges that were 

advertised as colored lamps (e.g., blue, green, orange, and magenta). DOE found these lamps 

only in the MH market, and they represented less than two percent of MH lamp catalog 

offerings. This small market share indicates a lack of potential for significant energy savings. 

DOE is considering identifying and defining these colored lamps by color rendering index 

(CRI)gbased on the observation that these lamps have very low CRI such that they emit light 

that appears colored. Because of their unique colored light output, such lamps are used for 

specialized applications and are unsuitable substitutions for other white-light emitting HID 

lamps. By examination of HID lamp offerings currently on the market, DOE preliminarily 

concluded that advertised colored MH lamps generally have a CRI less than 40. As such, DOE is 

not considering standards for those MH lamps that fall below a CRI of 40 due to their use in 

specialty applications and minimal energy savings potential. 

 

g

 CRI is a measure of how closely a light source reproduces the color of an object relative to a natural light source. 

Higher CRI is a closer match. 
3-8 

DOE also considered adopting the European Union’s (EU) definition of white light, 

which sets chromaticity requirements based on coordinates of the CIE 1931 chromaticity 

diagram.h DOE preliminarily determined that a colored MH lamp could be effectively defined 

using the simpler CRI criteria specified in the previous paragraph. 

3.2.2.8 MV Lamps for Specialty Applications 

The Energy Policy Act of 2005 banned the sale of MV lamp ballasts, but exempted 

ballasts for certain specialty applications, such as quality inspection, industrial processing, or 

scientific use, including fluorescent microscopy and ultraviolet curing. These applications cannot 

be served by other HID or solid-state lighting technologies due their unique need for the 

ultraviolet light emitted by MV sources. To preserve the market presence of the lamps that are 

intended for use with these exempted specialty application MV ballasts, DOE is considering 

excluding from energy conservation standards MV lamps that are individually labeled for 

specialty application, including the intended application. 

3.2.2.9 Electrodeless HID Lamps 

DOE has determined preliminarily that “electrodeless HID lamps” meet the definition of 

an HID lamp as defined in section 3.2.1. Electrodeless HID lamps generate light through a 

similar process, but couple power to the arc tube through means other than electrodes. Based on 

comments received in response to the framework document, the lighting industry generally 

considers electrodeless HID lamps to be a separate lamp technology, and not a subset of HID 

lamps. However, DOE determined that the definition of HID lamp as defined in section 3.2.1

does not make a distinction between lamps that do or do not have electrodes. 

The definition of HID lamp has four main specifications: (1) the arc tube wall loading is 

in excess of three watts/cm2; (2) the light-producing arc is stabilized by the arc tube wall 

temperature; (3) the lamp is either a MV, HPS, or MH lamp; and (4) the lamp is an “electricdischarge lamp.” Electrodeless HID lamps meet both the first and second criteria based on the 

high power density contained in the gaseous chamber. Regarding the third criteria, electrodeless 

HID lamps have a similar gas mixture to and produce light in the same manner as MH lamps, 

and meet the EPCA definition of a MH lamp. For the fourth criteria, the term electric discharge 

lamp is not defined in DOE’s regulations. DOE found that industry also does not have a 

definition of this term, so DOE reviewed industry’s usage of ‘electric-discharge lamp’ in 

available technical literature to understand its meaning.i Based on this review, DOE considers an 

electric discharge lamp to be any device that that uses a flow of electric charge in a gas to 

generate visible light through collision of charged particles and possibly other processes. 

Electrodeless HID lamps use this mechanism for generating light, and therefore meet the fourth 

specification of an HID lamp. Thus, DOE has determined preliminarily that “electrodeless HID 

lamps” meet the definition of an HID lamp. 

 

h

 For the complete EU definition of “white light source”, please see the Official Journal of the European Union, 

Commission Regulation (EC) No. 245/2009 of 18 March 2009 at: http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:076:0017:0044:EN:PDF. 

i Electric Discharge Lamps. John F. Waymouth. The Massachusetts Institute of Technology, 1971. 

The Lighting Handbook, Ninth Edition. The Illuminating Engineering Society, 2000. 

The Lighting Handbook, Tenth Edition. The Illuminating Engineering Society, 2011. 
3-9 

Although DOE considers electrodeless HID lamps to be a type of HID lamp, 

electrodeless HID lamps have very small market share (less than one percent) and do not have an 

industry consensus test method. DOE has evaluated this information and is not considering 

standards for electrodeless HID lamps in the interim analysis. 

3.2.2.10 Summary 

In summary, DOE is considering energy conservation standards for MH lamps with a 

rated wattage of ≥50 W and ≤2000 W, and MV and HPS lamps with a rated wattage of ≥50 W 

and ≤1000 W. Within those wattage ranges, DOE is considering standards for MH lamps with 

CCTs ≥2800 K and <7000 K, MV lamps with CCTs ≥3200 K and ≤6800 K, and HPS lamps with 

CCTs ≥1900 K and ≤2700 K. 

DOE is considering excluding directional HID lamps, self-ballasted HID lamps, HID 

lamps designed and labeled for use with electronic ballasts only, pulse-start MH lamps with CRI 

≥95, colored MH lamps (CRI less than 40), MV lamps intended for specialty applications, and 

electrodeless lamps from standards in this interim analysis. 

3.3 MARKET ASSESSMENT

The following market assessment identifies the manufacturer trade association and 

domestic manufacturers of HID lamps; discusses manufacturer market share, regulatory 

programs, and non-regulatory initiatives; defines product classes; provides historical shipment 

data, shipment projections, and equipment lifetime estimates; and summarizes market 

performance data. 

3.3.1 Trade Associations 

The National Electrical Manufacturers Association (NEMA) is the trade association for 

HID lamps. NEMA’s Lighting Systems Division is one of eight product divisions, performs 

numerous technical projects including MH lamp-ballast compatibility research and lighting 

application white papers, and supports the lighting industry on other activities including industry 

positions on legislative and regulatory initiatives.1

The division’s approximately 45 member 

companies comprise 75 to 80 percent of the domestic HID lamp market in terms of lamp sales. In 

addition to HID lamps, NEMA’s Lighting Systems Division also oversees products such as 

lighting controls, luminaires, solid-state lighting, and other lighting technologies. NEMA 

provides an organization through which manufacturers of lighting equipment can work together 

on projects that affect their industry and business. NEMA’s activities relating to energy 

efficiency include: 

• “[a]dvising the DOE and executive agencies on lighting research and market 

transformation needs; 

• engaging in legislative work on energy and lighting issues; 

• monitoring energy-efficiency rulemakings and standards affecting lighting products by 

federal and state agencies; 
3-10

• promoting the national voluntary luminaire rating and information program under the 

National Lighting Collaborative; 

• supporting adoption of 2010 ASHRAE/IESNA 90.1 lighting provisions; 

• working with market transformation and environmental groups to advance market use of 

energy-efficient lighting technologies; 

• advising DOE and the U.S. Environmental Protection Agency (EPA) on ENERGY STAR 

Buildings and ENERGY STAR voluntary product labeling programs; and 

• advocating market-based approaches to enhance the use and penetration of energyefficient technologies.” 

3.3.2 Manufacturers and Market Share 

The following list contains the names of manufacturers that produce HID lamps: 

• EiKO Limited 

• EYE Lighting 

• Fulham Incorporated 

• General Electric Consumer & Industrial 

• W.W. Granger, Inc. 

• Halco Lighting Technologies 

• Havells Ltd. 

• Howard Industries 

• Litetronics International, Inc. 

• OSRAM SYLVANIA 

• Philips Lighting

• Ruud Lighting, Inc.,

• Technical Consumer Products, Inc. 

• Ushio America, Inc. 

• Venture Lighting International 

• Westinghouse Lighting 

Four manufacturers hold the majority of the domestic market share of HID lamps: 

• GE Consumer and Industrial of General Electric, Inc. (hereafter, “GE”) 

• OSRAM SYLVANIA of Siemens AG (hereafter, “OSRAM SYLVANIA”) 

• Philips Lighting (hereafter, “Philips”) 

• Venture Lighting International (hereafter, “Venture”) 

 

 The lighting divisions of some of these companies also manufacture other products, such 

as fluorescent lamps, halogen lamps, light-emitting diodes (LEDs), and compact fluorescent 

lamps (CFLs). 
3-11

3.3.3 Small Businesses 

Small businesses may be particularly affected by the promulgation of energy 

conservation standards for HID lamps. The Small Business Administration (SBA) lists small 

business size standards that are matched to industries as they are described in the North 

American Industry Classification System (NAICS). A size standard is the maximum size that a 

for-profit company can be and still qualify as a small business for Federal government programs. 

These size standards are generally the average annual receipts or the average employment of a 

firm. For HID lamps, the size standard is matched to NAICS code 335110, Electric Lamp Bulb 

and Part Manufacturing, which has a size standard of 1,000 employees or fewer.2

DOE will study the potential impacts of the introduction of energy conservation standards 

on these small businesses in detail during the manufacturer impact analysis, which it will 

conduct as part of the notice of proposed rulemaking. 

3.3.4 Regulatory Programs 

Several federal, state, and international regulatory programs affect the market for HID 

lamps in the United States. The following section summarizes U.S., Canadian, and European 

regulatory initiatives relevant to the lamps covered by this rulemaking. While the following 

discussion is not exhaustive in describing all regulatory action related to HID lamps, it provides 

detail on some notable initiatives that characterize recent developments in the lighting market. 

3.3.4.1 Federal Energy Conservation Standards 

EPCA established an energy conservation program for certain industrial equipment. (42 

U.S.C. 6311–6317) The Energy Policy Act of 1992 (EPACT 1992), Pub. L. No. 102–486, 106 

Stat. 2776 amended EPCA to expand title III to include HID lamps in the program. Specifically, 

EPACT 1992 amended section 346 of EPCA to provide in paragraph (a) that the Secretary of 

Energy must prescribe testing requirements and energy conservation standards for those HID 

lamps that the Secretary determines that standards “would be technologically feasible and 

economically justified, and would result in significant energy savings.” (42 U.S.C. 6317(a)(2))

DOE conducted previous analyses to estimate the likely range of energy savings and 

economic benefits that would result from energy conservation standards for HID lamps. These 

documents were published in June 2003 and December 2004.j DOE then conducted additional 

analyses on the impacts of energy conservation standards and published supporting technical 

documents in April 2010 and July 2010. 75 FR 22031 (April 27, 2010) and 75 FR 37975 (July 1, 

2010) The July 2010 final determination concluded that energy conservation standards for HID 

lamps are technologically feasible, economically justified, and would result in significant energy 

savings, culminating in a positive final determination. 

 

j

 These documents may be accessed on DOE’s webpage at: 

www1.eere.energy.gov/buildings/appliance_standards/commercial/pdfs/hid_draft_report.pdf and 

www1.eere.energy.gov/buildings/appliance_standards/commercial/pdfs/hid_energy_savings_report.pdf. 
3-12

On February 21, 2012, DOE published a framework document for HID lamps that 

explained the analyses that DOE would conduct to evaluate establishing energy conservation 

standards for HID lamps.kThis interim analysis is a continuation of those analyses. 

3.3.4.2 California Energy Commission 

The California Energy Commission (CEC) established California’s Appliance Efficiency 

Regulations in 1976 that specifies requirements for both federally-regulated appliances and nonfederally regulated appliances. The standards “apply to appliances that are sold or offered for 

sale in California, except those sold wholesale in California for final retail sale outside the 

state.”

3 Although the regulations define HID lamps, they do not set minimum efficiency 

requirements for these products. However, the CEC does regulate luminaires, including MH 

luminaires. The CEC set energy efficiency standards and energy design standards for luminaires, 

including standards for MH luminaires in two phases with the first applying to MH luminaires 

sold in California and manufactured before January 1, 2009, and the second to MH luminaires 

manufactured on or after January 1, 2010. The standards for MH luminaires manufactured before 

January 1, 2009 are summarized in Table 3.3.1 below. 

Table 3.3.1 CEC Standards for MH Luminaires Manufactured Before January 1, 2009 

Lamp Position Lamp 

Rating

Effective 

Date Requirements

Vertical 

(Base-Up) 150-500 W Jan 1, 2006 Luminaires shall not contain a probe-start MH ballast.

Vertical 

(Base-Down) 150-500 W Jan 1, 2008 Luminaires shall not contain a probe-start MH ballast.

All 150-500 W Jan 1, 2008 Luminaires shall not contain a probe-start MH ballast.

All 150-500 W Jan 1, 2008

Luminaires with MH lamps shall contain MH ballasts with 

a minimum ballast efficiency of 88 percent. 

Exceptions: 

1. Luminaires that use electronic ballasts that operate 

at 480 volts; or 

2. Luminaires that meet all of the following criteria: 

 a. rated only for 150 watt lamps; and 

 b. rated for use in wet locations as specified by the 

National Electrical Code 2002, Section 410.4(A); and 

 c. contain a ballast that is rated to operate at ambient air 

temperatures above 50° C as specified by UL 1029-2001.

Notes: Luminaires are covered if they are capable of operating lamps within the range of included lamp 

wattages. Vertical includes products rated only for use within 15° of vertical. 

For MH luminaires manufactured on or after January 1, 2010, the CEC set energy 

efficiency standards that require that MH luminaires that are rated at least partially within the 

range of 150 to 500 W must not incorporate probe-start ballasts and must comply with the 

following requirements: 

 

k

 This document may be accessed on DOE’s webpage at: 

www1.eere.energy.gov/buildings/appliance_standards/pdfs/hid_ecs_framework_document.pdf. 
3-13

1. Indoor MH luminaires manufactured on or after January 1, 2010 shall comply with at 

least one of the following compliance options: 

A. A minimum ballast efficiency of 90 percent for 150 to 250 W lamps; or 92 

percent for 251 to 500 W lamps. 

B. A minimum ballast efficiency of 88 percent and an occupant sensor which is 

an integral control, shipped with the factory default setting to automatically 

reduce lamp power through dimming by a minimum of 40 percent within 30 

minutes or less after an area has been vacated; 

C. A minimum ballast efficiency of 88 percent and an automatic daylight control 

which is an integral control, shipped with the factory default setting to 

automatically reduce lamp power through dimming by a minimum of 40 

percent; 

D. A minimum ballast efficiency of 88 percent and a relamping rated wattage 

within only one of the four wattage bins: 150-160 W; 200-215 W; 290-335 W; 

or 336-500 W, provided that when a luminaire is able to operate 336 to 500 W 

lamps, the luminaire shall be prepackaged and sold together with at least one 

lamp per socket, having a minimum lamp mean efficacy of 80 lumens per watt 

[lm/W] based on published mean lumens and rated lamp power. The luminaire 

shall be able to operate lamps within only one of the four wattage bins and 

shall not be rated for any lamp wattage outside of that wattage bin. The 

luminaire shall have a permanent, pre-printed factory-installed label that states 

the relamping rated wattage. 

Exceptions to the CEC standards include that the following MH lighting systems 

shall not have probe-start ballasts and are not required to meet the minimum ballast 

efficiency requirements: 

A. Luminaires that use regulated lag ballasts; 

B. Luminaires that use electronic ballasts which operate at 480 volts; or 

C. Luminaires that meet all three of the following requirements: are rated for use 

only with 150 watt lamps; are rated for use in wet locations, as specified by 

the National Electrical Code 2002, Section 410.4(A); and contain a ballast that 

is rated to operate at ambient air temperatures above 50 degrees C, as 

specified by UL 1029-2001. 

2. Indoor MH luminaires manufactured on or after January 1, 2015 shall comply with 

item 1.D above, and shall also comply with at least one other compliance option of 

item 1 above. 

3. Outdoor MH luminaires manufactured on or after January 1, 2010, may comply with 

item 1.C above, and shall comply with at least one other compliance option of item 1 

above. 
3-14

3.3.4.3 Canadian Energy Efficiency Standards 

The Natural Resources Canada (NRCan) Office of Energy Efficiency does not currently 

regulate the energy efficiency of HID lamps in Canada. However, NRCan Office of Energy 

Efficiency proposed to amend Canada’s Energy Efficiency Regulations to include certain HID 

lamp ballasts in May 2010.4The HID lamp ballasts covered in the Canadian rulemaking do not 

include regulated lag ballasts, electronic ballasts that operate at 480 volts, ballasts rated only for 

150 W lamps, ballasts rated and marketed for use in wet locations, or ballasts rated and marketed 

to operate at ambient air temperatures above 50°C. Table 3.3.2 shows the proposed Canadian 

standards for HID lamp ballasts. 

Table 3.3.2 Canadian Proposed Standards for HID Lamp Ballasts 

Ballast Type Lamp Rated Wattage Minimum Rated Ballast 

Efficiency (%)

Magnetic Probe Start 150-500 W 94

Pulse Start 150-500 W 88

Non Pulse Start 

Electronic

150-250 W 90

251-500 W 92

The Canadian standards listed above apply to residential and commercial ballasts. 

Canadian standards consider an input voltage of 347 V in addition to 120 V and 277 V, which is 

consistent with the Canadian electrical distribution network. Canadian standards also require a 

minimum power factor of 0.9 (consistent with U.S. standards) for all ballasts except residential 

ballasts. Amendment 13, published in November 2011, updated the previous regulatory 

standards proposals to apply only to MH lamp ballasts used in new fixtures and to exclude 

ballasts intended for use as replacement ballasts and ballasts that are used with lamps rated 

between 150 and 500 watts, inclusive. 

3.3.4.4 European Energy Efficiency Regulations 

Commission Regulation (EU) No 347/2010 (April 21, 2010) amended Commission 

Regulation (EC) No 245/2009 (March 18, 2009), which implemented Directive 2005/32/EC 

(July 6, 2005) of the European Parliament and the Council of the European Union and amended 

Council Directive 92/42/EEC and Directives 96/57/EC and 2000/55/EC (September 18, 2000) to 

establish a framework for setting energy-efficiency requirements for energy-using equipment, 

including HID lamps and the ballasts and luminaires that are used with these lamps. The energyefficiency requirements apply to equipment available on the market and do not differentiate 

requirements by lamp application.5,6

The European energy-efficiency requirements regulate the covered equipment in stages. First 

stage requirements began in 2010 and did not cover HID lamps. Second stage requirements 

begin in 2013, requiring HID lamps to comply with the efficacies and performances listed in the 

Table 3.3.3 through Table 3.3.6, unless otherwise noted. Third stage requirements begin in 2018, 

requiring HID lamps to reach the efficacies and performances listed levels in the Table 3.3.7 and 
3-15

Table 3.3.8. The EU assigns different requirements to HID lamps based on the nominal wattage 

and bulb finishl(i.e., clear versus not clear). 

In addition to lamp efficacy, the EU includes requirements for lamp lumen maintenance 

factor, or LLMF, and lamp survival factor, or LSF, in its regulations. LLMF describes how 

bright a lamp remains as a percentage of the original brightness after a given period of time. LSF 

describes how long a lamp lasts before ceasing to function and requiring replacement due to 

cessation of function and is expressed as a percentage of the number of lamps still working after 

a specified period of time. Both of these factors are used in the European energy efficiency 

requirements. 

Table 3.3.3 Minimum Efficacy EU Requirements for HPS Lamps with a Color Rendering 

Index (Ra)m≤ 60 (Second Stage) 

Nominal Lamp 

Wattage

Rated Lamp Efficacy 

for Clear Lamps*

Rated Lamp Efficacy –

Not Clear Lamps*

W ≤ 45 ≥ 60 ≥ 60

45 < W ≤ 55 ≥ 80 ≥ 70

55 < W ≤ 75 ≥ 90 ≥ 80

75 < W ≤ 105 ≥ 100 ≥ 95

105 < W≤ 155 ≥ 110 ≥ 105

155 < W ≤ 255 ≥ 125 ≥ 115

255 < W ≤ 605 ≥ 135 ≥ 130

*These requirements also apply to HPS retrofit lamps designed to operate 

on high-pressure MV lamp ballasts beginning in 2016.

Table 3.3.4 Lumen Maintenance and Lamp Survival Factors for HPS Lamps (Second 

Stage) 

HPS Lamp Category and Burning Hours for 

Measurement

Lamp Lumen 

Maintenance 

Factor*

Lamp Survival 

Factor*

W ≤ 75

12,000 burning 

hours

Ra ≤ 60 > 0.80 > 0.90

Ra > 60 > 0.75 > 0.75

All retrofit lamps designed 

to operate on a MV ballast > 0.75 > 0.80

W < 75

16,000 burning 

hours

Ra ≤ 60 > 0.85 > 0.90

Ra > 60 > 0.70 > 0.65

All retrofit lamps designed 

to operate on a MV ballast > 0.75 > 0.55

*These requirements also apply to retrofit lamps designed to operate on high-pressure MV lamp 

ballasts beginning in 2016.

 

l

 Bulb finish is discussed in more detail in section 3.5.3. 

m

 The term color rendering index or CRI (also expressed as Ra) means the measure of the degree of color shift 

objects undergo when illuminated by a light source as compared with the color of those same objects when 

illuminated by a reference source of comparable color temperature. 42 U.S.C. 6291(30)(J) 
3-16

Table 3.3.5 Minimum Efficacy EU Requirements for MH Lamps with Ra ≤ 60 and for HPS 

Lamps with Ra > 60 (Second Stage) 

Nominal Lamp 

Wattage

Rated Lamp Efficacy 

for Clear Lamps

Rated Lamp Efficacy –

Not Clear Lamps

W ≤ 55 ≥ 60 ≥ 60

55 < W ≤ 75 ≥ 75 ≥ 70

75 < W ≤ 105 ≥ 80 ≥ 75

105 < W≤ 155 ≥ 80 ≥ 75

155 < W ≤ 255 ≥ 80 ≥ 75

255 < W ≤ 405 ≥ 85 ≥ 75

Table 3.3.6 Minimum Efficacy EU Requirements for other HID Lamps (Second Stage) 

Nominal Lamp Wattage Rated Lamp Efficacy*

W ≤ 40 ≥ 50

40 < W ≤ 50 ≥ 55

50 < W ≤ 70 ≥ 65

70 < W ≤ 125 ≥ 70

125 < W ≥ 75

*These requirements apply to all other HID lamps that are not 

covered in Table 3.3.3 through Table 3.3.5 beginning in 2016.

Table 3.3.7 Minimum Efficacy EU Requirements for MH Lamps (Third Stage) 

Nominal Lamp 

Wattage

Rated Lamp Efficacy 

for Clear Lamps

Rated Lamp Efficacy –

Not Clear Lamps

W ≤ 55 ≥ 70 ≥ 65

55 < W ≤ 75 ≥ 80 ≥ 75

75 < W ≤ 105 ≥ 85 ≥ 80

105 < W≤ 155 ≥ 85 ≥ 80

155 < W ≤ 255 ≥ 85 ≥ 80

255 < W ≤ 405 ≥ 90 ≥ 85

Table 3.3.8 Lumen Maintenance and Lamp Survival Factors for MH Lamps (Third Stage) 

Burning Hours Lamp Lumen 

Maintenance Factor Lamp Survival Factor

12,000 > 0.80 > 0.80

An additional definition was added to 2009/245/EC from 2010/347/EU for a “blended 

lamp” as follows: 

“(o) ‘Blended lamp’ means a lamp containing a mercury vapor lamp and an incandescent 

lamp filament connected in series in the same bulb.” 

Exemptions from the requirements include the following: 

“(c) blended high intensity discharge lamps having: 

- 6% or more of total radiation of the range 250-780 nm in the rage of 250-400 nm; and 
3-17

- 11% or more of total radiation of the range 250-780 nm in the rage of 630-780 nm; 

and

- 5% or more of total radiation of the range 250-780 nm in the range of 640-700 nm; 

(d) blended high intensity discharge lamps having: 

- The peak of the radiation between 315-300 nm (UVA) or 280-315 nm (UVB); 

(g) high intensity discharge lamps with Tc>7000K; 

(h) high intensity discharge lamps having a specific effective UV output > 2 mW/klm; 

and

(i) high intensity discharge lamps not having lamp cap E27, E40, PGZ12.” 

3.3.5 Non-Regulatory Initiatives 

DOE reviewed several national, regional, and local voluntary programs that promote the 

use of energy-efficient lighting in the United States. These include the Federal Energy 

Management Program’s (FEMP’s) program for energy-efficient lighting, the ENERGY STAR 

Program, the Energy Efficient Commercial Deduction, Efficiency Vermont, the Pacific Gas and 

Electric rebate program, the San Diego Gas and Electric Energy Efficiency Business Incentives 

program, the Omaha Public Power District incentives program, the Lyon-Lincoln Electric 

Cooperative, Inc. incentive program, and the North Carolina Municipal Power Agency 1. The 

following sections summarize some of these programs for the HID lamps covered by this 

rulemaking. While it is not an exhaustive list, the discussion provides detail on some notable 

initiatives that characterize recent developments in the lighting market. 

3.3.5.1 Federal Energy Management Program 

The Federal Energy Management Program (FEMP) helps Federal buyers identify and 

purchase energy-efficient products, including certain HID lamps. Section 104 of EPACT 2005 

requires that each agency incorporate energy-efficiency criteria consistent with ENERGY STAR 

and FEMP-designated products for “...all procurements involving energy consuming products 

and systems...” Executive Order 13123 and Federal Acquisition Regulation (FAR) section 

23.704 direct agencies to purchase products in the upper 25 percent of energy efficiency. 64 FR 

30851, 30854 (June 8, 1999). FEMP provides recommendations for how to purchase the energyefficient products, including the MH lamps shown in Table 3.3.9.

7

FEMP also offers buyers 

support tools such as efficiency guidelines, cost-effectiveness examples, and a cost calculator, as 

well as training, on-site audits, demonstrations, and design assistance. 
3-18

Table 3.3.9 FEMP Efficiency Requirements for Federal Purchases 

MH Lamps

Upward 

Efficiency Lamp Wattage Required Luminaire Efficacy Rating (LER)

Closed Fixture Open Fixture

0%

150–399 W ≥50 ≥49

400–999 W ≥62 ≥69

≥1000 W ≥84 ≥76

1–10%

150–399 W ≥68 ≥49

400–999 W ≥73 ≥75

≥1000 W ≥71 ≥96

11–20%

150–399 W ≥70 ≥55

400–999 W ≥76 ≥81

≥1000 W ≥82 ≥87

20%

150–399 W ≥76 ≥80

400–999 W ≥76 ≥70

≥1000 W ≥87 ≥93

Upward efficiency is the portion of light directed up by the fixture. Both high-bay and low-bay HID 

luminaires are available with opaque reflectors, which direct all or most of the light downward, and 

with transparent reflectors, which direct some light up. 

3.3.5.2 ENERGY STAR 

ENERGY STAR is a joint program of DOE and the Environmental Protection Agency 

(EPA) designed to protect the environment by promoting energy-efficient products and 

practices.8

ENERGY STAR specifies criteria for residential lighting fixtures, which contain three 

parts: a lamp, a ballast, and the fixture that holds the lamp and ballast. Products that qualify for 

the ENERGY STAR label may not use magnetic ballasts in indoor fixtures. The ENERGY 

STAR specifications also define criteria for lamp start time, power factor, lamp current crest 

factor, ballast operating temperature, electromagnetic interference, frequency, transient 

protection, end of life protection, dimming, and safety.9

ENERGY STAR also specifies criteria for certain luminaires. To qualify a luminaire for 

ENERGY STAR, the luminaire must first be identified as directional or non-directional (omnidirectional), then residential or commercial. HID lamps may be used to meet both the directional 

and non-directional ENERGY STAR requirements. Table 3.3.10 and Table 3.3.11 summarize all 

of the requirements associated with using to meet the ENERGY STAR residential and 

commercial directional and residential non-directional luminaire requirements, respectively.10
3-19

Table 3.3.10 ENERGY STAR Residential and Commercial Directional Luminaire 

Requirements 

Luminaire Type

ENERGY STAR Residential Requirements

Initial Efficacy Minimum Initial Lumen 

Output

Cove Mount 45 lm/W 200 lumens per lineal foot

Downlights 42 lm/W ≤ 4.5” aperture: 345 lumens 

> 4.5” aperture: 575 lumens

Accent Lights 35 lm/W 200 lumens per head

Outdoor PostMounted 35 lm/W 300 lumens

Luminaire Type

ENERGY STAR Commercial Requirements

Initial Efficacy Minimum Initial Lumen 

Output

Downlights 42 lm/W ≤ 4.5” aperture: 345 lumens 

> 4.5” aperture: 575 lumens

Table 3.3.11 ENERGY STAR Residential Non-Directional Luminaire Requirements 

Effective

ENERGY STAR Requirements*

Initial Efficacy Minimum Initial Lumen 

Output

Until September 1, 

2013 ≥ 65 lm/W per lamp-ballast platform**

800 lumens from lamp-ballast 

platform with the exception of 

chandeliers and bath vanity 

luminaires featuring ≥ heads 

which shall provide a minimum 

of 450 lumens per head.

After September 1, 

2013 ≥ 70 lm/W per lamp-ballast platform**

* MH, ceramic metal halide (CMH), or high-pressure sodium (HPS) lamps can be used to meet these 

requirements.

**These initial efficacy requirements have the exception of covered and dimmable versions of the 

GU24 based self-ballasted lamps that are required to meet reduced efficacy requirements as outlined in 

qualification requirements for those lamps.

EPA is currently developing a new product specification for lamps which will replace 

existing CFL and integral light-emitting diode (LED) lamp specifications. EPA published a Draft 

3 Version 1.0 Specification updating testing requirements, performance tiers, labeling 

requirements, and various other requirements, but did not specify performance characteristics of 

HID lamps.11

3.3.5.3 Energy Efficient Commercial Building Deduction 

EPACT 2005 created the Energy Efficient Commercial Buildings Deduction (26 U.S.C 

179D), which establishes a tax deduction of up to $1.80 per square foot for building owners who 

incur expenses for energy-efficiency upgrades that reduce energy costs by 50 percent or more. 

Effective for property in service from January 1, 2006 through December 31, 2008, the 

deduction allows partial deduction of $0.60 per square foot for improvements in interior lighting 

designed to reduce energy costs by one-third of the 50 percent requirement. Though the statute 

does not specify required lamp types or efficacies, it does call for an overall reduction in lighting 
3-20

power density (to qualify, the lighting power density must be below the minimum required by 

the ASHRAE/IES 90.1), encouraging the use of higher-performance and reduced-wattage HID 

lamp-and-ballast systems. The Emergency Economic Stabilization Act of 2008 (HR-1424), 

approved and signed on October 3, 2008, extends the benefits of EPACT 2005 through 

December 31, 2013. 

3.3.5.4 Efficiency Vermont 

Efficiency Vermont provides technical assistance, rebates, and other financial incentives 

to help Vermont households and businesses reduce energy costs with energy-efficient equipment, 

lighting, and other approaches. They are operated by the nonprofit organization Vermont Energy 

Investment Corporation under an appointment issued by the Vermont Public Service Board. 

Efficiency Vermont and the Burlington Electric Department partner with electrical distributors to 

offer contractors and commercial lighting customers efficient lamp replacements in order to 

reduce lighting energy consumption through the SMARTLIGHT Program. Through this 

program, Efficiency Vermont pays the incremental cost of energy-efficient lighting products 

directly to the distributor to help contractors and commercial lighting customers afford more 

energy-efficient replacement lamps. Reduced-wattage MH lamps are included in the eligible 

products through SMARTLIGHT. SMARTLIGHT offers payments ranging from $10 to $15 for 

reduced-wattage MH lamps from four manufacturers for lamps ranging from 60 to 950 watts. 12

3.3.5.5 Pacific Gas and Electric 

Pacific Gas and Electric (PG&E) offers rebates for businesses who purchase approved 

energy-efficient products for their companies. Funding for the rebate program is first-come, firstserve until their allocated funds are exhausted or the program ends, whichever comes first. 

PG&E offers rebates for several HID lamps and fixtures that meet their energy-efficiency 

requirements, summarized in Table 3.3.12.

13
3-21

Table 3.3.12 PG&E HID Lamp and Fixture Rebates (2013-2014) 

Description Rebate/Unit Measure

Indoor HID Fixtures with Electronic Ballasts

Existing > 400 W Lamp, ≤ 600 W New Lamp (Tier 1)* $20.00/fixture

Existing > 400 W Lamp, ≤ 750 W New Lamp (Tier 2)* $15.00/fixture

Existing 400 W Lamp, ≤ 250 W New Lamp $10.00/fixture

Existing 176 - 399 W Lamp, ≤ 150 W New Lamp $10.00/fixture

Existing 101 - 175 W Lamp, ≤ 125 W New Lamp $10.00/fixture

Existing ≤ 100 W Lamp, ≤ 70 W New Lamp $5.00/fixture

Outdoor HID Fixtures with Electronic Ballasts

Existing > 400 W Lamp, ≤ 750 W New Lamp $20.00/fixture

Existing > 400 W Lamp, ≤ 250 W New Lamp $15.00/fixture

Existing 201 - 399 W Lamp, ≤ 175 W New Lamp $15.00/fixture

Existing 176 - 200 W Lamp, ≤ 125 W New Lamp $10.00/fixture

Existing 101 - 175 W Lamp, ≤ 100 W New Lamp $10.00/fixture

Existing ≤ 100 W Lamp, ≤ 70 W New Lamp $5.00/fixture

* See section 3.3.4.2 for information on energy efficiency standards set by the CEC. Tier 1 refers to 

lamps that comply with standards set for lamps manufactured on or after January 1, 2010, and Tier 

2 refers to lamps that comply with standards set for lamps manufactured on or after January 1, 

2015.

 In order to receive the PG&E rebates for purchasing the indoor and outdoor HID fixtures 

with electronic ballasts, the business must install new pulse-start MH fixtures or retrofits with 

electronic HID ballasts. Furthermore, the retrofit kits and new fixtures must be equipped with 

pulse-start MH or ceramic metal halide (CMH) lamps and electronic ballasts that are compatible 

with controls and capable of dimming or bi-level functionality. The new fixtures must not exceed 

the “new lamp” wattages that are listed in Table 3.3.12. The new lamp wattage is the total lamponly wattage. Outdoor street and roadway installations do not qualify.14

3.3.5.6 San Diego Gas and Electric Company 

The San Diego Gas and Electric Company (SDG&E) operates a program called Energy 

Efficiency Business Incentives (EEBI) that offers incentive payments to any commercial, 

industrial, or agricultural customer who pays the public goods charge and/or demand-side 

management surcharge for energy-efficiency projects that involve the installation of new, highefficiency equipment or systems. The qualifying projects may consist of the retrofit of existing 

equipment. Incentives through EEBI are paid based on the quantity of kilowatt-hours (kWh) 

saved from the installation of the new equipment or system. The incentive for lighting is $0.05 

per kWh and $100 per peak kW. Program incentive funds will be allocated on a first-come, firstserve basis until all funds are committed, or until October 15, 2014, whichever comes first. 15

SDG&E also offers rebates for business entities that purchase and install higher 

efficiency HID fixtures and lamps. These rebates are summarized in Table 3.3.13.

16
3-22

Table 3.3.13 SDG&E HID Lamp and Fixture Rebates 

Description Rebate/Unit Measure

Indoor Pulse-Start MH and CMH Fixtures with Electronic Ballast

251 - 600 W New Lamp $20.00/fixture

601 - 750 W New Lamp $15.00/fixture

176 - 250 W New Lamp $10.00/fixture

126 - 175 W New Lamp $10.00/fixture

≤ 125 W New Lamp $10.00/fixture

≤ 70 W New Lamp (Pulse-Start MH only) $5.00/fixture

Outdoor Pulse-Start MH and CMH Fixtures with Electronic Ballast

251 - 750 W New Lamp $20.00/fixture

176 - 250 W New Lamp $15.00/fixture

126 - 175 W New Lamp $15.00/fixture

101 - 125 W New Lamp $10.00/fixture

71 - 100 W New Lamp $10.00/fixture

≤ 70 W New Lamp $5.00/fixture

CMH

≤ 75 W New CMH Fixtures $45.00/fixture

Similar to PG&E, in order to receive the rebate for both indoor and outdoor fixtures with 

electronic ballasts, SDG&E requires new pulse-start MH fixtures or retrofit kits with electronic 

ballasts. Also, the retrofit kits and new fixtures must be equipped with pulse-start MH or CMH 

lamps and electronic ballasts that are compatible with controls and capable of dimming or bilevel functionality. The retrofit kits may also be used on existing MV, probe-start MH, or HPS 

fixtures. In order to receive the rebate for CMH fixtures and lamps, the business must replace 

existing incandescent, PAR halogen, or PAR halogen IR lamps with one listed in Table 3.3.13

for accent lighting, flood lighting, or down lighting in indoor installations. 

3.3.5.7 Omaha Public Power District 

The Omaha Public Power District (OPPD) offers lighting incentives to commercial and 

industrial customers for replacing and retrofitting their current lighting systems to more energyefficient ones. Table 3.3.14 summarizes the financial incentives that OPPD offers related to HID 

retrofits and replacements.17,18
3-23

Table 3.3.14 OPPD 2013 Retrofit and Replacement Incentives 

Current System Proposed System Incentive Amount/Unit

400 to 999 W HID Reduced W Direct MH Replacement $26.00

320 to 350 W pulsestart MH Reduced W Direct pulse-start MH Replacement $18.00

250 W HID Reduced W Direct MH Replacement $15.00

175 W HID Reduced W Direct MH Replacement $15.00

3.3.5.8 Lyon-Lincoln Electric Cooperative, Inc. 

Lyon-Lincoln Electric Cooperative, Inc. (LLEC) is a rural electric cooperative that 

provides services to its members including developing energy-efficient solutions for buildings, 

homes, transportation, power systems and industry, and energy-efficient products for their 

members. LLEC also provides lighting rebates for new and retrofit applications. They require 

that retrofit systems result in a net load reduction in kW from that of the existing lighting system. 

The LLEC lighting rebate program provides rebates only for indoor lighting.19

Although LLEC did not list the rebate amounts, the eligible rebates are as follows: 

 Replacing an incandescent, HPS, or MV fixture with an MH fixture with the MH lamp 

wattage lower than the existing lamp wattage 

 Replacing an incandescent or MV fixture with an HPS fixture with the HPS lamp wattage 

lower than the existing lamp wattage 

 Replacing an incandescent, halogen, MV, HPS, MH, or pulse-start MH fixture with a 

CMH lamp fixture with the lamp wattage lower than the existing lamp wattage 

 Replacing an incandescent, MV, HPS, or MH with a pulse-start MH fixture with the lamp 

wattage lower than the existing lamp wattage20

3.3.5.9 North Carolina Municipal Power Agency 1 

The North Carolina Municipal Power Agency 1 (NCMPA1) consists of 19 cities and 

towns in North Carolina. It funds several energy-efficiency programs available to the NCMPA1 

participants to encourage energy conservation and efficient energy use. In February 2009, 

NCPMA1 launched the Hometown Green program, which runs the NCMPA1 Lighting Rebate 

Program and provides commercial and industrial customers with rebate incentives for energyefficient technologies. This program provides examples of anticipated projects that include 

replacing HID lamps with T-8 or T-5 fluorescent lamps. The NCMPA1 Lighting Rebate program 

grants a rebate of $0.35 per watt saved, with a maximum rebate of $25,000 per customer based 

on total energy saved from energy-efficient lighting retrofits to existing buildings. Minimum 

operating hours per year of 1,800 are required to be eligible for incentives. All fixtures, lamps, 

and ballasts must be UL certified and meet applicable codes and regulations.21

3.3.6 Historical Shipments 

Awareness of annual lamp shipment trends is an important aspect of the market 

assessment and the development of the standards rulemaking. For this rulemaking, DOE used 

two sets of HID lamp shipments that NEMA provided for the periods 1990 to 2002 and 2003 to 
3-24

2008.

22 DOE also obtained NEMA HID lamp indices series and confidential shipments from 

NEMA for 2009 and 2010. Based on manufacturer feedback from interviews, NEMA represents 

100 percent of domestic HID lamp production and 75 to 80 percent of national HID lamp sales. 

The HID lamps in the shipment values include colored and directional lamps, which DOE is 

considering exempting from this rulemaking. 

DOE used this data for two main purposes. First, the shipment data and market trend 

information contributed to the shipments analysis and base-case forecast for HID lamps. By 

using historical shipment data and expert opinion on market trends and calibrating forecast 

assumptions with recent data, DOE believes it has based the shipments model and base-case 

forecasts on a sound dataset. Second, DOE used the data to develop the installed stock of HID 

lamps for the national impact analysis (chapter 11 of the interim TSD). Based on its 

understanding of trends in the market, DOE estimated how the market would respond to various 

candidate standard levels. 

The historical shipment data for HID lamps is broken down into the main HID lamp 

technologies including MV, MH, and HPS lamps. Figure 3.3.1 depicts the historical shipments of 

each lamp type and the projected shipments through 2010. 

Figure 3.3.1 Shipments of HID Lamps 

In 1990, pulse-start MH and CMH lamps were a new lamp technology, while the other 

HID lamp types were established in the domestic market. HPS, MV, and probe-start MH lamps 

shared similar shipments because they were the three main lamp types used for indoor and 

outdoor commercial and industrial applications. As customers requested more efficient lamps, 

the shipments of pulse-start MH and CMH lamps began to increase, while the less-efficient MV 

 -

 2.0

 4.0

 6.0

 8.0

 10.0

 12.0

 14.0

 16.0

 18.0

 20.0

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Shipments (millions)

Year

High Pressure Sodium

Mercury Vapor

Probe-Start MH

Pulse-Start and Ceramic MH
3-25

lamp shipments began to drop. HPS lamps, although efficient compared to the other HID lamp 

types, have a lower color temperature than the other HID lamp types, resulting in a yellow color. 

Because of this, the shipments of HPS lamps remained relatively steady while the whiter-light 

MH lamps increased in shipments in more recent years. Although probe-start and pulse-start MH 

lamps provide similar color temperatures, the pulse-start MH lamps are generally more efficient 

than the probe-start, leading to a decrease in probe-start MH shipments in recent years. 

Furthermore, recent regulation set by EISA 2007 required higher efficiency MH ballasts, further 

transitioning shipments from probe-start to pulse-start and CMH lamps in recent years, as shown 

in Figure 3.3.1. 

Figure 3.3.2 HID Lamp Market Share by Lamp Type 

As previously mentioned, shipments of HPS, MV, and probe-start MH lamps were 

similar in 1990 when they were the main commercial and industrial lamp types. As the more 

efficient HPS and MH lamps were introduced to the market, MV lamps quickly ceded market 

share to MH lamps. In 1990, MV lamps represented approximately 32 percent of all HID lamp 

shipments, whereas in 2010 they comprised approximately five percent. From 2000 onward, 

pulse-start and ceramic MH lamps gained market share because of their energy efficiency and 

superior color characteristics. Between 2004 and 2008, the market began to stabilize, with no 

drastic redistribution of market share between HID lamp types. In anticipation of the January 1, 

2009 effective date of an EISA 2007 provision that effectively prohibited the use of probe-start 

MH ballasts with luminaires containing lamps between 150-500W, pulse-start and CMH lamps 

began to absorb some of the market share of probe-start MH lamps in 2008. Since then, pulsestart and CMH lamps market share has increased at the expense of probe-start MH lamps. The 

2010 market share distribution between lamp types is shown in Figure 3.3.3.

0%

10%

20%

30%

40%

50%

60%

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Market Share

Year

High Pressure Sodium

Mercury Vapor

Probe-Start MH

Pulse-Start and Ceramic MH
3-26

Figure 3.3.3 2010 HID Lamp Market Share

Table 3.3.15 shows the breakdown of HID lamp shipments 1990 to 2010. As previously 

mentioned, all HID lamp shipments include colored and directional lamps, which DOE is 

considering excluding from energy conservation standards. 

34%

33% 5%

29% HPS

MV

Probe MH

Pulse MH

and CMH
3-27

Table 3.3.15 Historical Shipments of HID Lamps 

Unit Shipments (millions) by Year

HPS MV Pulse

MH & CMH Probe MH

1990 7.4 6.2 --- 5.7

1991 8.2 4.5 --- 5.5

1992 8.8 4.7 --- 6.4

1993 9.7 4.6 --- 7.3

1994 10.6 4.8 --- 8.7

1995 10.8 4.5 --- 10.5

1996 11.9 4.4 0.05 11.5

1997 11.9 3.5 0.1 13.1

1998 12.2 2.8 0.4 15.0

1999 12.6 3.0 0.9 17.2

2000 11.5 2.8 1.3 16.8

2001 11.5 2.1 2.7 15.6

2002 11.7 2.3 3.8 15.0

2003 11.5 2.3 4.7 14.5

2004 11.3 2.3 7.2 12.7

2005 13.9 2.3 7.9 13.6

2006 11.8 2.7 7.9 14.0

2007 11.2 2.3 7.9 14.1

2008 10.9 1.8 7.3 13.0

2009 10.2 1.5 8.6 10.9

2010 10.2 1.5 9.9 8.8

3.4 TECHNOLOGY ASSESSMENT

The purpose of the technology assessment is to develop a preliminary list of technologies 

that could be used to improve the efficacy of HID lamps. The following assessment provides a 

description of the basic construction and operation of MV, HPS, and MH lamps, including 

technology options to improve efficacy. 

3.4.1 Basic Structure and Operation of HID Lamps 

All HID lamps produce light by converting electrical energy into kinetic energy of 

moving electrons, which is then converted into radiation primarily through collisional excitation 

of gaseous atoms.23 The gaseous atoms are contained in an arc tube inside the bulb of the lamp 

and are typically metals, such as mercury or sodium, or halide compounds of metals.24 Starter 

gases that ionize at relatively low pressures are also present—usually argon or xenon or a 

mixture of argon, neon, or xenon, depending on the type of HID lamp.24 HID lamps also contain 

buffer gases, which serve to increase the pressure inside the arc tube to vaporize the lightproducing molecules. The arc tube also contains electrodes, typically made of tungsten, that 

deliver an electric field to the arc tube. 
3-28

The outer bulb that contains the arc tube is made of soft or hard glass (though usually 

hard glass).n It protects the arc tube and internal electrical connections from being exposed to the 

environment. The atmosphere in the outer bulb is often a vacuum—though sometimes a lowpressure gas such as nitrogen is present in the outer bulb—in order to prevent oxidation of the 

arc tube metal parts and to reduce gaseous convective heat loss from the arc tube.24 The outer 

bulb also acts as a shield to prevent direct contact with the inner arc tube during lamp handling 

and installation. If a quartz arc tube is handled directly, the salts present in human perspiration 

can deposit onto the surface of the silica wall of the arc tube. These salts provide crystal nuclei 

onto which the amorphous silica can crystallize. Over extended lamp operation, the crystallized 

areas can grow such that the differential expansion between crystalline quartz and vitreous silica 

could cause failure of the arc tube.23

While the outer bulb transmits light, it absorbs most of the UV radiation emitted by the 

arc tube. The outer bulb is sometimes coated with a diffusing material to decrease source 

brightness of the lamp. The diffusing coating is typically a color-correcting phosphor which 

converts the UV radiation emitted by the arc tube to visible light in order to improve the lamp’s 

overall color rendering properties and sometimes efficacy.o,24 The outer bulb also contains 

electrical wiring, which conducts electricity to the arc tube, and structural components to support 

the arc tube. Other components such as resistors or diodes, which help start the arc discharge, 

and getters, components that purify the atmosphere in the outer lamp by removing trace gases, 

may also be present within the outer bulb.24 Finally, HID lamps usually have screw bases, though 

some lamps have special bi-pin bases or pairs of single-contact bases at each end of the lamp. 

When voltage is applied across the electrodes, free electrons get accelerated within the 

arc tube until an arc is ignited between the main electrodes. The heat generated by this process 

causes the metal or metal halide atoms in the arc tube to vaporize, diffuse into the arc, and, in the 

case of metal halide lamps, the metal halides dissociate. In the arc stream, free electrons collide 

with the gaseous metal atoms, thereby exciting the electrons within the atoms to higher, unstable 

energy states. As the electrons drop back to the stable or ground energy state, they emit 

electromagnetic radiation that is equivalent to the energy difference between the excited energy 

state and stable energy state.23 The free electrons again collide with the gaseous atoms, excite the 

atoms’ electrons, and the entire process is repeated.23 This process is shown schematically in 

Figure 3.4.1 below. 

 

n

 Hard, or borosilicate, glass has a higher melting point and lower coefficient of expansion than soft glass. Hard 

glass, therefore, can withstand higher temperatures and pressures than soft glass. 

o

 The color-correcting properties of the phosphor diffusing coating have the largest effect on MV lamps because MV 

lamps emit the most UV radiation. 
3-29

Figure 3.4.1 Light Emission Process of an HID Lamp 

3.4.2 Mercury Vapor Lamps 

MV lamps were introduced in the 1930s and were the first commercially available HID 

lamps. The CRI of these lamps is relatively poor, such that most objects appear to have distorted 

colors. For example, orange and red appear brownish, and blue, green, and yellow are 

emphasized.24 Therefore, MV lamps are primarily used in applications that are not frequently 

occupied by people. Typical applications include outdoor security, street lighting, and landscape 

lighting. However, more-efficient HPS and MH lamps are replacing MV lamps in some of these 

applications. 

Based on a review of manufacturer catalogs,pthe initial efficacy of MV lamps ranges 

from 31 lm/W to 64 lm/W, with typical efficacies around 45 lm/W. The CCT typically ranges 

from 3200 K to 5700 K, while CRI typically ranges from 20 to 50. The higher CRI values are 

achievable through the use of phosphor coatings on the inside of the outer bulb. The typical rated 

life of MV lamps is about 24,000 hours. 

3.4.2.1 Lamp Construction 

Figure 3.4.2 shows the detailed construction of a MV lamp. MV lamps produce light 

when an electric current is passed through mercury vapor. Mercury, along with argon, which is 

used as the starter gas, is contained within an arc tube typically made of fused silica (quartz). 

Current conductor ribbons made of molybdenum are sealed into the ends of the arc tube.24 This 

seal is the lead-in connector that transmits current to the lamp electrodes. Directly sealing the 

silica arc tube to the molybdenum ribbons ensures a hermetic seal because, despite a difference 

in coefficients of expansion, the molybdenum foil can yield plastically (permanently deforming 

under stress) under high thermal stresses.23 The ability to withstand high-temperature is 

important because the minimum wall temperature of the arc tube in MV lamps is typically in 

excess of 357°C, the boiling point of mercury.23

 

p

 Fourteen HID lamp manufacturer catalogs were reviewed to create a database of approximately 2,600 HID lamps. 

The excited state is unstable; therefore, 

the atom emits electromagnetic 

radiation as it falls to a lower energy 

state, which may or may not be the 

ground state. Electrical energy in the 

form of current (i.e. free 

moving, accelerated 

electrons)

Atom within the arc tube 

of the HID lamp that 

exists in its ground energy 

state

Atom in the excited 

state after the 

external electron 

collision

Electromagnetic spectrum
3-30

Figure 3.4.2 Mercury Vapor Lamp Construction24

In addition to the starter gas and mercury, the arc tube also contains electrodes, which are 

usually made of tungsten. The emission material in the electrodes, which comprises several 

metallic oxides, is embedded within the turns of a tungsten coil and protected by an outer 

tungsten coil.24 The arc tube of most MV lamps also contains an auxiliary starting electrode, 

which is placed near one of the main electrodes and connected to the opposite main electrode 

through a current-limiting resistor.q,24 The inclusion of a starting electrode allows the arc to strike 

at 50 percent of the starting voltage that would be required without it.23 

The arc tube is enclosed within an outer bulb that is usually elliptical in shape, made of 

hard (borosilicate) glass, and contains a stable, low-pressure gas, which is generally nitrogen or, 

in rare cases, a vacuum.24 In addition to the functions described in section 3.4.1, the outer bulb 

serves a particularly important function in MV lamps: that of absorbing ultraviolet (UV) 

radiation. The emission spectrum of mercury includes unusually high radiation in the UV 

wavelengths that penetrates the silica walls of the arc tube. Without the outer bulb, the UV rays 

present in the emitted light could harm people exposed to the light by causing severe sunburns or 

a painful burn to the conjunctiva of the eye.23 Though the borosilicate glass of the outer bulb 

absorbs much of the UV light, the inner surface of the outer bulb is usually coated with phosphor 

coatings, which reduce UV transmittance further by converting some of the emitted UV rays into 

visible light.24 Generally, the phosphor is chosen to emit in the red region, thereby significantly 

 

q

 Some special MV lamps do not use a starter electrode, but instead require a high open-circuit voltage to ionize the 

argon starting gas until an arc can strike across the electrodes. These two-electrode MV lamps are uncommon and 

are used in specialty applications.24
3-31

improving the color rendering of the lamp. In doing so, the phosphor coating also slightly 

improves efficacy. 

3.4.2.2 Lamp Operation 

The majority of MV lamps are probe-start lamps, which have a starting electrode adjacent 

to one of the main electrodes.rThe voltage gradient across this small gap between the starting 

and adjacent electrodes is high enough to ionize the argon gas. As electrons are freed by this 

ionization process, they are accelerated by the electric field between the main electrodes until an 

arc strikes between the main electrodes. After an arc is established between the main electrodes, 

a bimetal switch removes the starting electrode from the circuit. 

Because mercury has a low vapor pressure, it cannot be vaporized until sufficient heat is 

generated in the arc tube. Therefore, argon is used as a starter gas at pressures of 2.4 to 4.8 kPa to 

facilitate lamp starting.25 Because it ionizes more readily than mercury, argon is first to ionize 

and is responsible for establishing an arc between the main electrodes. Once an arc has been 

struck, heat generated within the arc tube begins to vaporize the mercury and the process 

continues until all the mercury is evaporated.24 The time required from starting the lamp to 

vaporizing the mercury is known as the warm-up time. At the end of the warm-up period, the 

lamp operates at steady state with all of the mercury evaporated. 

When the lamp is first ignited, the arc tube is at ambient temperature and the mercury 

pressure is low.23 The lamp voltage is low at the instant the arc strikes but rises through the 

warm-up phase until the arc attains a stable vapor pressure. The operating pressure depends on 

the amount of mercury in the lamp and varies between 200 to 400 kPa in most lamps.24 For a 

lamp to reach these high operating pressures, the arc tube must warm up to a minimum of 500 

°C; it typically takes five to seven minutes to reach this operating temperature and pressure. 

During the warm-up phase, the arc stream changes from a bluish glow, which is produced 

when argon is ionized, to a blue-green light once mercury starts vaporizing. The blue-green light 

increases greatly in luminance and becomes concentrated along the axis of the arc tube as more 

mercury vaporizes.24 Once a MV lamp is turned off, the lamp will not reignite until the mercury 

pressure has decreased substantially and the arc tube cools down sufficiently, to approximately 

125 °C.23 The vapor pressure must decrease to the point where the arc can restrike at the 

available voltage for the lamp to restart.24 The time required for hot restart of the lamp, or restriking the arc after a momentary power loss and sufficient cooling, is between three to six 

minutes for most MV lamps. 

MV lamps produce light when an electric current is passed through mercury vapor at high 

pressure. During steady state operation, the spectral power distribution of the lamp depends on 

the pressure at which the lamp operates. At higher operating pressures, the majority of the 

emitted radiation is in the longer wavelengths because the electrons within the mercury atom are 

excited to higher energy states. As the electrons fall back to lower energy states, they emit light 

 

r

 Some special MV lamps do not use a starter electrode, but instead require a high open-circuit voltage to ionize the 

argon starting gas until an arc can strike across the electrodes. These two-electrode MV lamps are uncommon and 

include specialty applications. 24
3-32

with longer wavelengths. These longer wavelengths fall in the visible region of the 

electromagnetic spectrum with the five principle visible spectrum lines of mercury at 404.7, 

435.8, 546.1, 577, and 599 nm.24 These lines are consistent with the greenish-blue light of MV 

lamps. Figure 3.4.3 shows the spectral power distribution for MV lamps. At extremely high 

pressure, there is also a tendency of the line spectrum to spread into wider bands.24 

Along with emissions in the visible spectrum, a significant portion of the energy emitted 

by MV lamps is in the UV region with wavelengths of 185.0 and 253.7 nm. Phosphor coatings 

applied on the inside wall of the outer bulb help convert some of the emitted UV rays to visible 

radiation. In general, the phosphor is selected such that it converts UV radiation to emit in the 

red region of the spectrum.23 Because there is no radiation in the red region of the mercury 

spectrum, this greatly improves the color of the phosphor-coated lamp. The phosphor used most 

commonly for coating MV lamps is a vanadate phosphor, which emits long-wavelength radiation 

in the orange-red region of the visible spectrum.24 This phosphor is also blended with others to 

produce cooler or warmer colors as needed. The use of phosphors improves the efficacy and 

color rendering of MV lamps. Phosphor-coated MV lamps are often preferred over clear lamps 

due to their improved color rendering.23

Figure 3.4.3 Mercury Vapor Spectral Power Distributions24

Over the operating life of MV lamps, lumen depreciation occurs due to the deposition of 

evaporated electrode material on the walls of the arc tube.23 The process of evaporation and 

deposition of the electrode emission material initially deposits a white material on the inner 

surface of the arc tube, which eventually turns black. The emission material is deposited on the 

walls of the arc tube very slowly because it has to evaporate and diffuse through mercury vapor, 

which is a very heavy gas at high pressure.23 Therefore, MV lamps have a long average rated life 

and excellent maintenance of light output over the life of the lamp. At 24,000 hours, a typical 

MV lamp continues to emit 75 percent of its initial light output.23 The lamp reaches the end of its 

life when the electrodes are exhausted and when the starting voltage exceeds the open-circuit 

voltage.24
3-33

3.4.3 High-Pressure Sodium Lamps 

HPS lamps were introduced in the 1960s and are generally the most efficacious lamps 

within the HID family. However, the color rendering of these lamps is poor and they are 

therefore used in applications where color characteristics are not crucial.26 The most common 

application of HPS lamps is for street lighting applications, though they are common in exterior, 

security, and industrial lighting applications as well. The initial efficacy of HPS lamps ranges 

from 46 lm/W to 153 lm/W, with typical efficacy around 100 lm/W. 

The CCT and CRI ranges of typical HPS lamps are not as varied as other HID lamps, 

with CCT typically ranging from 1900 K to 2200 K and CRI typically ranging from 20 to 25. In 

addition to standard HPS lamps, HPS lamps with higher CCT and CRI values are available, but 

such lamps have much lower efficacy compared to typical HPS lamps. HPS lamps have a very 

long life with a typical rated life of 24,000 hours. 

3.4.3.1 Lamp Construction 

Figure 3.4.4 shows the basic components of an HPS lamp. As the name suggests, HPS 

lamps produce light when current is passed through sodium vapor at high pressure. Consistent 

with typical HID lamp construction, HPS lamps have an inner arc tube and an outer bulb. Arc 

tube materials that are used in other HID lamps, such as quartz, cannot be used for HPS lamps 

because sodium is highly corrosive, particularly at high temperatures. Instead, the arc tube of 

HPS lamps is made of polycrystalline alumina (ceramic, or PCA), which is resistant to the 

corrosive nature of sodium at high temperatures and has a high melting point.24 Polycrystalline 

alumina is translucent, yet it transmits more than 90 percent of the light.24 For a brief period 

beginning in the late 1970s, some manufacturers also produced HPS lamps with a synthetic 

sapphire arc tube. Like PCA, sapphire is a form of aluminum oxide (Al2O3). However, it is 

grown as a single crystal from molten alumina. As such, it is far purer and denser, and its 

superior mechanical properties allow it to withstand a higher wall loading and achieve higher 

efficacy. Furthermore, sapphire is a transparent crystal, allowing a higher transmittance of light 

as compared to PCA, and therefore a three to eight percent increase in efficacy.27 Despite 

superior performance of sapphire arc tubes, however, these lamps are no longer in production 

due to costly materials and manufacturing processes. 

The contents of the arc tube include electrodes, sodium and mercury amalgamsas the 

light-emitting gas, and xenon as the starter gas. The sodium and mercury amalgam typically 

forms at the coldest spot within the arc tube.28 An advantage of including the amalgam reservoir 

inside the arc tube is that HPS lamps can be operated in any physical orientation; therefore, HPS 

lamps cannot be misinstalled.28

 

s

 An amalgam is an alloy of mercury. Sodium and mercury amalgam is an alloy of sodium and mercury. 
3-34

Figure 3.4.4 High-Pressure Sodium Lamp Construction24

Because the ceramic used to make the arc tube of HPS lamps is crystalline, it cannot be 

flame-worked (fused to metal by melting), like glass or quartz, to make conventional electrode 

seals. Therefore, an end cap, usually made of niobium, is brazedt

or weldeduto the electrode 

lead-in wire and support. Niobium is used because it has a thermal expansion coefficient that is 

very close to that of translucent ceramic, and it therefore maintains a seal as the ceramic expands 

and contracts with temperature variation. This end cap assembly is then fastened to the ceramic 

arc tube by a brazingv

or frit-sealing technique.w,23 Figure 3.4.5 shows the cross section of a 

typical seal assembly for an HPS lamp. 

 

t

 Brazing is a process to join metals wherein a filler material is heated above its melting point and distributed 

between two or more close-fitting parts by capillary action. 

u

 Welding is a process to join materials, usually metals or thermoplastics, by melting the materials to be joined and 

adding a filler material to form a pool of molten material. When the molten material cools, it becomes a strong joint. 

Welding differs from brazing in that in welding the materials to be joined are also melted, while they are not melted 

in brazing. 

v

 The brazing technique to attach the end cap assembly to the inner arc tube use a molten metal or metals that have a 

high affinity for both the alumina surface and the niobium end cap. These filler materials typically lack “wettability” 

with the alumina surface, but the advantage of brazing is that the filler materials are relatively nonpermeable to 

sodium metal. Therefore, sodium losses from the arc tube are minimized. 

w

 A frit seal employs a glassy or crystalline material of a lower melting point than alumina as a “glue” with which to 

stick on the end cap and inner arc tube. An advantage of the frit seal is that it “wets” the alumina surface better than 

the brazes do and tolerates a wider variation in spacing between the end cap and inner arc tube. The disadvantage of 

using a frit seal is that frit-sealed lamps show a higher rate of sodium loss from the arc tube than braze-sealed ones. 
3-35

Figure 3.4.5 Cross Section of a Typical Seal Assembly for an HPS Lamp with a Ceramic 

Arc Tube23

3.4.3.2 Lamp Operation 

HPS lamps produce light by the same basic mechanism as other HID lamps: an arc, 

sustained by a voltage across the operating electrodes, ionizes the gas into a plasma, excites the 

metal atom electrons to a higher energy state, and light is emitted as the gaseous atoms fall back 

to their ground energy state from the excited state. However, the starting mechanism is unique 

because the compact arc tube diameter and the presence of metal end caps used for sealing the 

electrodes to the arc tube preclude the use of a starting electrode.23,24 Instead, a high-voltage 

pulse starts the lamp. When the high-voltage pulse is applied across the electrodes within the arc 

tube, xenon gas is first ionized, which facilitates striking the arc. After sufficient heat is 

generated by the arc, the sodium and mercury amalgam begins vaporizing.26 The mercury vapor 

raises the gas pressure and operating voltage within the arc tube, which facilitates the sodium 

vapor’s production of light once sufficient pressure is reached within the arc tube. 

The phase before the sodium vaporizes sufficiently to produce a steady yellow light is 

known as the warm-up time. HPS lamps typically warm up for two to four minutes.29 During 

warm-up, HPS lamps pass through three distinct color phases. First, the lamp produces light of a 

sky blue color as the xenon ignites. As the mercury vaporizes, it emits a bluish color. As the 

A: alumina arc tube

B: niobium or stainless steel exhaust tube

C: niobium end cap

D: pinch seal

E: electrode

F: frit or braze seal

G: exhaust port
3-36

sodium vaporizes, the lamp finally stabilizes at the characteristic yellow-white light.30 After 

turning off an HPS lamp, either manually or due to power failure, it must cool down before the 

arc can restrike. The lamp generally requires one minute to restrike.29

While argon or neon is typically used as starter gases for other HID lamp technologies, 

xenon is used in HPS lamps because it has a lower thermal conductivity. This reduces gas 

conduction losses, thereby increasing the efficacy of the lamp. The HPS lamp also uses relatively 

high xenon pressures improve efficacy, though at the expense of a higher starting voltage. A 

typical xenon pressure in the arc tube is about 20 kPa.31 The sodium-to-mercury atomic ratio in 

the arc is approximately two or three atoms of sodium to one atom of mercury. 

Mercury, the buffer gas used to facilitate increasing the pressure within the arc tube to 

vaporize sodium, has several other benefits. It is easier to handle and dispense sodium as an 

amalgam of mercury rather than pure sodium. Further, the blue-green spectral emission of 

mercury combines with the yellow-orange of sodium to improve the color rendition of the lamp. 

Once the lamp is warmed up and enough sodium has been vaporized to operate in steady 

state, the lamp radiates energy in the visible spectrum, though the color of emitted light depends 

on pressure, with higher sodium pressures broadening the emission spectrum and improving 

CRI. The lamp produces a yellow-white light, which is created as the green-blue light of the 

mercury spectrum adds to the yellow-orange light of the sodium spectrum.23 At sodium pressures 

of 27 kPa or higher, the resulting spectrum is a nearly continuous one, with spectral absorption 

lines at 589.0 nm and 589.6 nm. These gaps in the emission spectrum, known as the D-lines of 

sodium, occur when photons in the characteristic monochromatic yellow-orange of low-pressure 

sodium are self-absorbed by nearby particles and reradiated in random directions, effectively 

scattering these photons into other wavelengths. The leftmost panel of Figure 3.4.6 shows the 

resulting spectral power distribution for a typical HPS lamp. Further increasing the sodium 

pressure within the arc tube broadens the emission spectrum and improves the color rendering 

qualities of the lamp at the expense of efficacy.31 As sodium pressure increases beyond an 

optimal pressure, the rate of photon absorption increases, effectively widening the D-lines and 

shifting the emission spectrum into the infrared. HPS lamps with CCTs of 2200 K to 2700 K and 

CRI between 65 and 85 have been developed by employing this method. These high-CRI lamps 

have shorter life (with a median of about 9,000 hours) and lower efficacy (between 46 and 94 

lm/W, with a median of 52 lm/W) than standard HPS lamps.24 The rightmost panel of Figure 

3.4.6 shows the spectral power distribution of a high-CRI lamp. 
3-37

Figure 3.4.6 High-Pressure Sodium Spectral Power Distributions24

The operating voltage of the arc tube in an HPS lamp increases over the life of the 

lamp.24 The cause for the increase in voltage is primarily due to the loss of sodium in the arc tube 

over the lamp life and the resulting change in the ratio of the sodium and mercury amalgam.32

Sodium is lost through several methods, such as leakage from the arc tube, reactions with the arc 

tube wall, and sodium loss to the electrode emission material.32 Toward the end of the lamp’s 

operating life, the voltage of the lamp may increase beyond the ballast’s capability to sustain the 

arc across the electrodes. When this happens, the lamp extinguishes, cools down, and turns on 

again. This cycling pattern repeats for a long time, usually until the lamp is replaced.32 If the 

lamp is not replaced within a reasonable period of time, the lamp may require more voltage than 

the ballast is designed to provide and the ballast may fail permanently. 

To overcome the issue of end-of-life cycling of HPS lamps, the industry introduced noncycling HPS lamps in the 1990s. These lamps operate on standard HPS ballasts but modify the 

conditions within the arc tube to prevent cycling. The electrode emissive coating material can be 

changed to decrease sodium losses to the emitter.32 Other methods have included dosing the 

lamp such that it is unsaturated in mercury and saturated in sodium.32 Adjusting the arc tube wall 

temperature and xenon pressure to reduce sodium loss due to reaction with the arc tube wall has 

also been researched.32 A starting aid is used in these lamps because the breakdown voltage of 

xenon increases with increasing pressure. These lamps gradually become fully unsaturated in the 

useful operating regime towards the end-of-life.32 

HPS lamps can be manufactured as retrofit lamps for MV lamp ballasts. These HPS 

lamps have an additional coil, called a starting aid, around the arc tube inside the outer bulb, 

which is connected through a thermal circuit breaker to the electrode at the opposite end of the 

tube. On applying a potential, the starting aid works similarly to the starting electrode in probestart MV and MH lamps in that ionization between the starting aid and adjacent electrode 

eventually allows an arc to form between the electrodes.28 These retrofit lamps use a combination 

of argon and neon gas as the starter gas instead of the xenon that is typically used in HPS lamps. 

Due to the unique voltage requirements of an HPS lamp, special care must be taken when 

selecting a ballast for an HPS lamp-and-ballast system. That is, the ballast of an HPS lamp must 
3-38

accommodate the changing voltage over the lamp’s life in order to maintain an acceptable 

average wattage. ANSI has developed standards for the maximum and minimum permissible 

lamp wattage and voltage for each nominal lamp voltage. The permissible operating parameters 

for a 400 W HPS lamp are shown in Figure 3.4.7 as an example. 

Figure 3.4.7 Operation Limits for 400 W HPS Lamp29

3.4.4 Metal Halide Lamps 

Metal halide lamps were commercially introduced in the 1960s and have since evolved 

into the most versatile lamp of the HID family, finding common use in applications such as 

roadway, sports fields, landscape, industrial, retail, floodlighting, and vehicular headlamps. They 

are very similar to MV lamps in basic construction, but the addition of a variety of metal halides 

to the gas composition gives them very good color rendering properties, with products available 

with CRI values ranging from 60 to 96 and CCT ranging from 2800 K to 50,000 K.xThe efficacy 

of MH lamps is also much improved over that of MV lamps, with initial efficacy ranging from 

60 to 125 lumens per watt. The typical rated life of MH lamps is about 15,000 hours. MH arc 

tubes can be made of either quartz or ceramic, and the lamps can employ either a probe-start or 

pulse-start mechanism for arc ignition. 

3.4.4.1 Lamp Construction 

MH lamps are constructed similarly to MV lamps with some notable differences. The arc 

tube of MH lamps is usually smaller than those of MV lamps of equivalent wattages and is often 

formed into a non-cylindrical shape to improve temperature uniformity in different operating 

positions.33 The arc tube can be made of fused quartz or ceramic and contains two main 

electrodes, a starting electrode in the case of probe-start MH lamps, argon as the starter gas, 

 

x

 Some directional MH lamps are available with a CCT as low as 2500 K. 
3-39

mercury as the buffer gas, and one or more metal halide compounds to improve the spectral 

emission of the lamp. The basic construction of a MH lamp is depicted in Figure 3.4.8. 

Figure 3.4.8 Metal Halide Lamp Construction24

Arc Tube Construction. MH lamps can be manufactured for dedicated horizontal 

operation, for dedicated vertical operation, or as a universal lamp that is capable of operating in 

either horizontal or vertical orientation. The orientation of the lamp affects the temperature 

gradient of the arc tube, in turn affecting lumen output and color. Excessive wall loading on the 

arc tube wall can also decrease life by approximately 25 percent.34 Depending on the operating 

orientation of the lamp, the arc tube shape is designed to optimize lumen output and color. For 

instance, lamps that are designed for operating exclusively in the horizontal orientation have an 

arc tube that is bow-shaped to follow the natural upward bowing of the arc during operation due 

to convection currents. The bow-shaped arc tube prevents migration of the chemicals by 

restricting them to the ends of the arc tube.24 Another design of an arc tube for horizontal 

operation is an asymmetric arc tube in which the electrodes are lower in the arc tube body, rather 

than the center. This design allows the arc to bow to the center line of the arc tube and prevents 

the arc from being too close to the top of the arc tube wall, causing its temperature to increase.24

Figure 3.4.9 shows these two common configurations for horizontal MH lamp arc tubes. MH 

lamps that are designed to operate in the horizontal orientation generally have a special base and 

socket, called position oriented mogul base (POMB), which ensure that the arc tube is properly 

oriented during installation and operation. 
3-40

Figure 3.4.9 Common Configurations for Horizontal Metal Halide Lamps24

The first MH lamps were probe-start MH lamps. The arc tube of probe-start MH lamps is 

made of quartz only. The classic arc tube design is generally referred to as pinched body and is 

shown in Figure 3.4.10.

24 Probe-start MH lamps have a secondary starting electrode, similar to 

MV lamps, that is used to start the lamp. The lamp also contains a system that provides for either 

shorting of the starting electrode to the main electrode or opening the starting electrode circuit 

after the lamp has started to prevent electrolysis in the fused silica between the starting electrode 

and main electrode—especially when a halide such as sodium iodide is used in the lamp—which 

can greatly shorten lamp life.24 A bimetal switch is typically used in the starter circuit to serve 

this function. The location and type of the switch could potentially restrict the lamp operating 

position because the bimetal switch needs to achieve a certain temperature for it to function.24 

Pulse-start MH lamps have also been designed with ovoid-shaped quartz arc tubes. These 

arc tubes are commonly referred to as formed body arc tubes because the arc tubes are formed in 

a mold using high-pressure gas.24 The formed shape of the arc tube has several benefits. For 

example, the contours of the arc tube wall better follow the shape of the arc and allow a more 

uniform thermal profile for the arc tube.24 The formed shape further allows the chemicals in the 

arc tube to heat up more rapidly compared to the pinched body arc tube, allowing formed body 

arc tubes to warm up approximately three times faster than pinched body arc tubes of the same 

wattage.24 The formed-body arc tube also has much smaller pinch seal areas, thereby reducing 

conductive heat loss through the pinch seals, where the temperature of the metal halide pool is 

generally lower than the rest of the arc tube. This reduction in the size of the pinch seals 

improves the efficacy of lamps with formed-body arc tubes. The magnitude of the efficacy 

improvement is more prominent in lower-wattage lamps because the pinch seal area in these 

lamps comprises a greater part of the total thermal mass of the arc tube.24 The smaller pinch seal 

does not permit the inclusion of a starting electrode; therefore, all MH lamps with formed-body 

arc tubes have only two main electrodes within the arc tube and employ the pulse-start 

mechanism.24
3-41

Figure 3.4.10 Common MH Arc Tubes: (a) Ovoid, (b) Pinched Body24

The arc tube walls of MH lamps usually operate at very high temperatures, in the range 

of 725–750 °C. However, it is important to ensure that the ends of the arc tube do not lose too 

much heat, especially for lamps that operate in the vertical position. To avoid this, the end of the 

arc tube is carefully contoured and a press seal design is used along with the application of a 

heat-insulating coating that reduces the infrared radiation leaving the arc tube ends.23 Zirconium 

oxide is typically used for coating the arc tube ends because it has good reflectivity in the 

infrared region and reflects the infrared radiation from the electrode back into the arc tube, 

thereby raising the end temperature.23 Coating the ends of the arc tube also increases the 

vaporization of the metal halides during operation.24

CMH lamps, the newest technology development for MH lamps, have an arc tube made 

of translucent polycrystalline alumina and were developed and commercialized in North 

America in the 1990s.35 The arc tube of these lamps is typically cylindrical in shape and can 

withstand metal iodide salt temperatures that are about 300 °C higher than quartz arc tubes can 

withstand.35 The higher operating temperature and pressure permitted by the ceramic arc tube in 

these lamps makes them more efficacious than quartz MH lamps. Further, the color consistency, 

color rendering, life, and lumen maintenance of these lamps are also remarkably improved.35

CMH lamps are designed to operate exclusively on pulse-start ballasts and thus do not have a 

starter-electrode. While the arc tube of CMH lamps is made of the same material as HPS lamps, 

the technique used to seal the electrodes into the arc tube is not the same. This is because the 

niobium end cap and sealing frit used in HPS lamps would be rapidly corroded by the liquid and 

gaseous metal halide compounds, causing leakage from the arc tube.36 Instead, a special design, 

as shown in Figure 3.4.11, is employed in CMH lamps, which consists of an extended plug, a 

niobium lead-in, a molybdenum lead-through, and the sealing frit that completely covers the 

niobium and partially covers the molybdenum.36 The frit is made of a mixture of aluminum, 

silicon, and rare-earth oxides, making it more resistant to corrosion compared to the frit 
3-42

employed in typical HPS lamps.36 This design, which is a variation of the HPS lamp 

construction, reduces the frit temperature to an acceptable level, and the frit layer reduces the 

transport rate to and from the niobium surface.36 A disadvantage of this construction is the 

possible formation of cracks in the alumina plug due to differences in the thermal expansion 

coefficients between the molybdenum lead-through and the alumina plug. This issue can be 

overcome either by using coiled molybdenum lead-through to redirect the stresses or by using 

molybdenum-alumina composite material that has a thermal coefficient of expansion that closely 

matches that of alumina.36

Figure 3.4.11 CMH Lamp Arc Tube Design 36

Figure 3.4.12 shows the arc tube designs of probe-start quartz MH, pulse-start quartz 

MH, and CMH lamps. 
3-43

Figure 3.4.12 Metal Halide Lamp Arc Tube Designs33

Additive Compounds. The choice of the metal halide compound(s) that is introduced in 

the MH arc tube is governed by the vapor pressure of the compound at the coldest spot of the arc 

tube.

23 A reasonable coldest-spot temperature in the arc tube of MH lamps is 1000 K, and the 

vapor pressure of the metal should be 130 Pa or higher at this temperature for the intensity of the 

spectra to be strong enough to produce a brilliant white light.23 Introducing the metal atom in 

MH lamps as a metal halide compound (i.e., instead of pure metal) has two important benefits. 

First, nearly all metal halide compounds have vapor pressures greater than 130 Pa at 1000 K.23

That is, at the arc tube operating temperature, metal halides are more volatile than pure metals 

and, therefore, normal arc tube wall temperatures are sufficient to obtain the emission properties 

of the metal.24 Second, with the exception of fluoride compounds, almost none of the metal 

halide compounds react appreciably with silica, unlike pure metals that react chemically with 

fused silica.23 These advantages allow nearly any metal of the periodic table—including those 

with more desirable emission spectra—to be introduced into the MH lamp arc tube, instead of 

the three or four metals otherwise possible.23 This allows manufacturers a greater degree of 

flexibility in optimizing operating temperature and pressure (and therefore efficacy) and color 

rendering. 

The metal halide compounds selected must meet two additional requirements. The 

compound must be stable at the wall temperature of the arc tube, while also being unstable at the 

temperatures corresponding to the light-emitting part of the arc column.23 Iodide compounds 

satisfy these stability criteria the best among the halide compounds and therefore, metal iodide 

compounds are the preferred additives in MH lamps.23 The final requirement is that the room 

temperature vapor pressure of the compound must be sufficiently low. This requirement is 

necessary because even a small amount of halide compounds in the vapor phase at the time of 

ignition greatly increases the starting voltage.23 In addition to satisfying the stability criteria, the 
3-44

iodide compounds of most metals meet the low vapor pressure at room temperature requirement 

as well. 

There are approximately 50 metal iodide compounds that can be used in different 

combinations in MH lamps.23 If two metals are used at a time in the arc tube of MH lamps, the 

number of possible combinations, without varying concentrations, is 1,225.23 With the addition 

of more metals, the possible combinations are several hundred thousand. With such a large 

number of possibilities, the choice of metal halide compounds is typically made based on the 

desired radiation spectrum from the lamp.23 For example, lamps for general lighting applications 

are typically white and utilize compounds that produce wavelengths across the visible spectrum. 

Photocopy or graphic arts applications typically require light sources with light in the blue and 

near-UV parts of the spectrum and therefore select additives that produce strong lines in this 

spectrum.23

In order to prevent metal condensation on the walls of the arc tube, excess iodine must be 

in the gas phase near the arc tube wall to ensure that the equilibrium between gaseous metal and 

metal iodide is strongly shifted towards the metal iodide compound. However, this cannot be 

accomplished by excess iodine itself. This is because excess iodine typically forms the diatomic 

iodine molecule, I2, near the arc tube wall, whose gas is purple and highly light-absorbing.23

Therefore, excess iodine is typically introduced in the form of mercury iodide, HgI2, which is 

unstable compared to diatomic iodine but is also transparent. The excess iodine combines with 

the metal vapor to form metal iodide, thereby preventing condensation of the metal on the arc 

tube walls.23 The ratio of iodine-to-mercury is typically controlled between 0.2 and 0.8.23

Alkali metal iodides, such as iodides of lithium, sodium, potassium, rubidium, and 

cesium, are generally added to the arc tube of MH lamps to overcome the issues of constricted, 

poorly wall-stabilized arcs and the resulting electrical resistance.23 The addition of alkali metal 

iodides, which have a lower ionization potential, to the arc tube “fattens” the arc. They do so by 

allowing free electrons to be present in the lower-temperature regions of the arc, thereby 

generating higher temperatures in that region and allowing more current to flow through the 

arc.23 The overall effect of this phenomenon is increased arc current and decreased arc voltage 

for a given lamp wattage.23 Sodium iodide is typically preferred as the alkali iodide to be 

introduced in the arc tube because of the strong emission in the yellow region of the spectrum of 

sodium, which increases the lumen output of the lamp.23 

Function of Mercury in Metal Halide Lamps. In addition to providing a suitable means 

to introduce excess iodine, mercury is an essential component in the arc tube of MH lamps for 

several other reasons. First, it provides a high total pressure in the arc tube during lamp operation 

while still having a low pressure at ignition, thereby allowing the lamp to be ignited at a 

reasonable starting voltage.23 High pressure during lamp operation is required to ensure that the 

dissociated metal and iodine atoms do not diffuse from the core of the arc to the arc tube wall 

because this phenomenon would lead to very significant loss of energy resulting in an inefficient 

lamp.23 Second, the presence of mercury ensures that any free iodine that is present in the arc 

tube during lamp starting is not present as diatomic iodine. This is important because the 

presence of free diatomic iodine vapor during lamp ignition makes the starting voltage very high 

due to the strong electron-attaching properties of diatomic iodine.23
3-45

Protective Shroud Cover. In some single-ended MH lamps, a transparent glass sleeve, 

called a shroud, is used to surround the arc tube. A thin-walled shroud is used as a heat shield 

because it allows the arc tube to achieve a uniform temperature while retarding sodium loss in 

lamps that contain sodium.24 

MH lamps operate at pressures far exceeding atmospheric pressure (generally 10 to 15 

atmospheres), and therefore there is a danger of violent rupture to lamps that are weakened by 

chemical degradation, manufacturing defect, or damage. As a precaution, a heavier shroud is 

used in lamps that are rated for open fixtures in order to contain hot lamp fragments in the event 

of an arc tube rupture. A quartz arc tube may rupture because of devitrification, which is a 

process wherein some sections of the quartz arc tube become crystalline while adjacent regions 

remain in the amorphous state, giving rise to regions of different thermal expansion.37 These 

regions of different thermal expansion within the same quartz arc tube cause the quartz to 

weaken and possibly crack.37 In the case where an arc tube ruptures from violent failure, the 

heavy shroud prevents the outer jacket of the lamp from breaking as well, thereby preventing 

humans from coming into contact with the chemicals from within the arc tube as well as the 

resultant broken glass.24 Therefore, it is very important that an open luminaire be relamped with 

an open-rated lamp only. Lamps that are rated for enclosed fixtures only must be operated in an 

enclosed luminaire that is designed to contain any hot fragments of an arc tube rupture.24 The 

industry has developed unique socket and base combinations for open-rated medium and mogul 

base lamps to prevent user misapplication.24 The industry has also developed S-rated lamps, 

which do not have a protective shroud, but may be installed in open fixtures if mounted base up, 

cycled off for at least 15 minutes a week, and relamped at 70 percent of rated lifetime, in 

adherence with manufacturer and NEMA guidelines.38 The safety of these lamps is somewhat 

controversial; as such, changes to the 2005 National Electrical Code (NEC), effective January 1, 

2005, eliminating the option of installed S-rated lamps in open luminaires for those installations 

regulated by the NEC. Some manufacturers still offer S-rated lamps.39

Another advantage of lamps with protective shrouds is that the shroud reduces UV 

radiation emitted from the lamp compared to MH lamps without a shroud.37 However, the safety 

benefits of a shroud come at the cost of reduced efficacy as the shroud also blocks some of the 

lamp’s visible light. 

Outer Bulb Construction. The outer bulb of MH lamps is typically elliptical in shape and 

is usually made of borosilicate glass. The environment of the outer bulb either contains a lowpressure inert gas such as nitrogen or is a vacuum, which controls the arc tube temperature and 

prevents oxidation of electrical components.24 Decreasing the gas pressure in the outer bulb 

increases the arc tube temperature for a given wall loading because the lower gas pressure in the 

outer bulb reduces convective cooling of the arc tube.23 While some manufacturers achieve this 

by providing an evacuated outer jacket, others accomplish it be using a slightly smaller arc tube 

in a gas-filled outer jacket.23

Most MH lamps also contain getters, or chemical additives in the outer bulb that reduce 

or eliminate impurities present in the outer jacket. These impurities are predominantly hydrogen 

and carbon. If the impurities are present in the outer bulb of an MH lamp in sufficient 
3-46

concentrations, they can corrode the lamp support structure and electrodes, thereby 

compromising performance of the lamp.24

The outer bulb can also be characterized by its bulb finish—that is, whether the inner 

wall of the outer bulb is coated with phosphors. Phosphor coating is generally used in MH lamps 

to create a more diffuse light source.24 Phosphor-coated bulbs block some of the light emitted 

from the arc tube, leading to lower overall efficacy compared to clear lamps. 

Finally, some MH lamps either have no outer jacket or they have an outer jacket that is 

made from fused silica and transmits UV energy. These lamps must be operated only in those 

fixtures that have a cover glass that provides UV filtration.24

3.4.4.2 Lamp Operation 

In addition to the argon and mercury present in MV lamps, MH lamps contain various 

metal halides.24 It is the metal atom of the metal halide compound that emits light when an 

excited electron falls back to lower energy states in a MH lamp. 

Probe-start MH lamps start with the aid of a starting electrode, similar to the starting 

method of MV lamps. A key difference between MH and MV lamps, however, is that the 

starting voltage of MH lamps is higher than that for MV lamps because of the presence of the 

metal halides.23,24 Pulse-start MH lamps do not have a starting electrode and instead use an 

igniter to provide enough voltage across the main electrodes to initiate an arc.24 Once an arc is 

initiated between the main electrodes, the lamp is in the warm-up phase, during which the color 

of the discharge continues to change as the metal halides warm up, evaporate, and get 

incorporated into the arc.24 MH lamps typically require between three to five minutes to warm 

up. If a MH lamp is turned off, it takes longer to cool down and reignite than a MV lamp. This is 

because the smaller arc tube of a MH lamp necessitates a higher operating temperature.24 The 

restrike time in the conventional pinched body arc tube is often 15 minutes or longer. In contrast, 

pulse-start MH lamps can restrike in as little as 4 to 5 minutes because of the higher pulse 

(starting) voltages.24,29

Once the lamp color and electrical characteristics stabilize, the lamp enters steady state 

operation. During this phase, when the lamp attains its full operating temperature, all the 

mercury is vaporized, which results in a high-pressure, wall-stabilized arc.23 As the metal iodides 

migrate closer to the arc tube walls, they evaporate and diffuse into the high-temperature arc 

column where they dissociate.23 The dissociated metal atoms are ionized and excited, causing 

them to emit light. Once the metal atoms diffuse towards the cooler walls of the arc tube, they 

recombine with the iodine atoms that are present in the cooler gas near the walls to reform metal 

iodide molecules.23 The cycle is then repeated with metal iodides moving into the hightemperature arc and dissociating to emit light from the metal atoms.24 The partial pressure of 

metal vapor at the arc axis is typically between 1.3 and 13 kPa and is comparable to the partial 

pressure of metal iodide vapor at the walls.23

The emitted spectrum is dependent on the metal atom or atoms present in the arc tube and 

their characteristic emission spectra.23 The emitted spectrum of a MH lamp typically consists of 

the spectrum of the metals with the mercury spectrum superimposed.23 While some metals 
3-47

produce visible radiation at a single wavelength, other metals may produce several discrete 

wavelengths across the visible and UV spectra, and many other metals may produce a continuous 

spectrum of radiation.24 Often, blends of metal halides are used to obtain the desired spectrum, 

and hence, the desired color characteristics of the lamp. 

Figure 3.4.13 Metal Halide Spectral Power Distributions24

3.4.5 HID Ballasts 

HID ballasts are “devices that, by means of resistance, inductance, capacitance, or 

electronic elements, singly or in combination, control the current, voltage, and waveform for 

proper lamp starting and operation.” (American National Standards Institute (ANSI) C82.9-

1996). The following sections discuss basic ballast operation of both ballast types: 

electromagnetic (magnetic) and electronic. 

A ballast has three primary functions: 

1. To establish an electric arc through the lamp 

2. To limit current through the lamp after ignition 

3. To compensate for variations in line voltage and ensure consistent lumen output 

Magnetic ballasts were the first technology used to operate lamps; electronic ballasts 

were developed later because of their higher efficiency. The following sections provide 

additional discussion on these types of ballasts. 

3.4.5.1 Magnetic Ballasts 

HID magnetic ballast technology is older than electronic ballast technology, and used 

today for its low cost and tolerance of harsh environments. The primary feature of a magnetic 

ballast is one or more coils of magnet wire around an iron core; because of this they are often 

called “core and coil” ballasts. Apart from the igniter of pulse-start ballasts, magnetic ballasts 

contain no power electronics and are, therefore, better equipped to survive voltage transients and 

high temperatures. 
3-48

The main components of a magnetic ballast are a magnetic choke to limit the current, a 

step-up transformer to obtain a high starting voltage, and a capacitor that corrects for the ballast’s 

low power factor. Magnetic ballasts operate at an input frequency of 60 Hz and operate the 

lamp(s) at the same frequency. 

The main core and coil assembly consists of a capacitor and laminated transformer steel 

wound with copper or aluminum magnet wire. The assembly is infused with a potting material 

(e.g., hot asphalt, epoxy) containing fiber such as silica and housed in a steel case. Figure 3.4.14

presents a view of a typical core and coil assembly. 

Source: GE Lighting

Figure 3.4.14 Core and Coil Assembly of a Magnetic Ballast 

The core and coil assembly functions as a voltage transformer and current limiter 

(choke). A capacitor enables the ballast to use energy from the alternating current power line 

more efficiently; the ballast is then referred to as a high power factor (HPF) or power factor (PF) 

corrected ballast. The purpose of the insulating material is to conduct heat away from the 

transformer coils and ensure tightness of the transformer coils to eliminate vibration noise. 

Particularly at lower wattages, magnetic ballasts are less energy efficient than electronic 

ballasts. In order of increasing cost and complexity, HID magnetic ballasts have the following 

types of circuits: linear reactor (reactor), high-reactance autotransformer (HX-HPF), constant 

wattage autotransformer (CWA), constant wattage isolated (CWI), and magnetically regulated 

lag (mag-reg or regulated lag). In general, extra circuitry helps the ballast maintain a constant 

power output through variations in input voltage. 
3-49

Linear Reactor. Reactor ballasts are the simplest, smallest, cheapest, and most efficient 

type of magnetic ballast. Though a capacitor is often employed for power factor correction, a 

reactor ballast can be as simple as a mere inductor in series with the load. A reactor ballast drops 

more voltage as current increases, stabilizing lamp current at the appropriate point. The major 

drawback of a reactor ballast is its susceptibility to line voltage variation; the commonly used 

ratio is a 5 percent voltage dip produces a greater than 10 percent power dip. Furthermore, the 

ballast can only limit current and has no ability to modify voltage, meaning the line voltage must 

be sufficient to run the lamp, often limiting reactor ballasts to 277 V applications. 

High-Reactance Autotransformer (HX-HPF). With high-reactance autotransformers, 

the addition of a capacitor to the primary circuit makes it possible for the ballast to provide a 

high power factor. The high power factor autotransformer is usually designed with an extra 

capacitor winding within its copper windings in order to provide a more economical and efficient 

system. The HX-HPF ballast’s power factor can be increased to about 90 percent by combining 

the extended windings with the capacitor. The input current is reduced, as in the high power 

factor reactor. Lamp performance and wattage are also regulated at plus or minus 5 percent. 

Currently, HX-HPF ballasts are commonly used with HID lamps that are rated at 150 W or less. 

Constant-Wattage Autotransformer (CWA). The CWA ballast type should be used 

where a stabilized light output is required. CWA is an HID ballast type that comes in a fairly 

small economical size, yet still provides a reasonable degree of wattage regulation. The CWA 

ballast also offers the advantage of a high power factor, low line extinguishing voltage, and line 

starting currents that are lower than operating currents. The CWA type of ballast is the most 

commonly used HID ballast in North America today. 

Unlike the HX-HPFs, which use a capacitor as a parallel component, the capacitor on a 

CWA ballast type is used in series with the lamp. This alignment provides the lamp with a more 

stable wattage when voltage on the branch circuit fluctuates. As the capacitor is performing an 

important ballasting function, it is referred to as a lead circuit. CWA is the most common ballast 

topology because of its ability to resist line voltage changes and for its lower starting current 

demands. Although some CWA units rated for lower than 150 W are sold, wattages higher than 

150 W are firmly CWA territory. 

Constant-Wattage Isolated Transformer (CWI). CWI ballasts are nearly identical to 

CWA ballasts in both structure and function, the primary difference being a conventional twocoil transformer in place of the single-coil autotransformer. At a very slight efficiency cost, CWI 

ballasts provide better protection against voltage transients, as the low and high sides of the 

ballast are coupled only magnetically. Though common in Canada, few CWI ballasts are sold in 

the United States. 

Magnetically Regulated Lag. Regulated lag ballasts are the largest, heaviest, and most 

expensive topology. Three distinct circuits collaborate to provide the greatest degree of 

resistance to voltage variation, and regulated lag ballasts may even sustain lamps through voltage 

drops of 30 percent. Regulated lag ballasts were exempted from standards in EISA 2007 and 

account for a very small (less than one percent) fraction of the North American ballast market. 
3-50

Due to their large size and high cost, regulated lag ballasts are unlikely to be substitutes for 

CWAs or other ballast types.

3.4.5.2 Electronic Ballasts 

Depending on wattage, electronic ballasts might be between 2 and 20 percent more 

efficient than their magnetic counterparts. Electronic ballasts can be roughly divided into lowand high-frequency types that, respectively, operate lamps far below or above frequency ranges 

prone to acoustic resonance. Most low-frequency electronic (LFE) ballasts drive their lamps with 

a “square” wave, while high-frequency electronic (HFE) units usually produce sinusoids. 

Although HFE units are thought by some to be more efficient because of smaller circuitry 

components and the elimination of a power processing stage from the ballast, high efficiency 

electronic HID ballasts can be found operating lamps at both high and low frequencies. Figure 

3.4.15 depicts a typical electronic HID ballast. 

Source: GE Lighting 

Figure 3.4.15 Electronic HID Ballast 

Figure 3.4.16 presents a functional block diagram example of a fixed-light output 

electronic ballast. Auxiliary functions performed by a typical electronic ballast include 

electromagnetic interference (EMI) filtering to block ballast-generated noise, input rectification, 

power factor (PF) correction for sinusoidal input current, a direct-current (DC) filter, a directcurrent to alternating-current (DC-AC) inverter, a feedback/controller for high-frequency 

operation, and a final output stage to power the lamp.

Figure 3.4.16 Electronic HID Ballast Block Diagram40

Table 3.4.1 provides a description of each component in a typical electronic HID ballast, 

the efficiency impact of these components, and the waveform at each stage of the ballast circuit. 
3-51

Table 3.4.1 Building Blocks of an HID Ballast and Associated Characteristics 

Circuit Stage Function Efficiency 

Impact

Waveform

(not to scale)

EMI Filter

Impedes EMI by providing a high impedance 

path to EMI and a low impedance path to the 

desired input. The circuit also protects against 

high voltage spikes.

Very Low

Input Rectifier

Begins to convert incoming AC to DC using 

diodes. A full-bridge rectifier, one type of 

input rectifier, is composed of four diodes, 

which “rectify” the full AC waveform as 

shown in the waveform on the right. The 

current is not in phase with the voltage.

Low

Power Factor 

Correction

Corrects the current so it is in phase with the 

voltage. Power factor correction can be 

achieved through a buck or boost-converter 

circuit topology.

Low-Medium

DC Filter

Reduces “ripple” of the DC current waveform 

using capacitors. The most common type of 

capacitor used is the electrolytic capacitor.

Low

DC-AC Inverter and 

Output Stage

Converts incoming DC to AC, sets the current 

to the lamp, and provides a high voltage pulse 

to start the lamp. The full-bridge (with 

integrated buck converter) circuit is one type 

of circuit topology that can be used to 

accomplish this task.

High

Feedback/Controller An integrated circuit (IC) that controls the 

frequency output of the DC-AC inverter. Low N/A

t

V

t

V, I

t

V, I

t

V

t

V
3-52

3.4.6 HID Fixtures 

The basic function of an HID fixture is to hold the lamp, supply electric power to the 

lamp via a ballast, and sometimes, direct the light as desired. A fixture typically comprises the 

lamp, ballast, ballast housing or structure, optics, and wiring.y An HID fixture is typically sold 

with the lamp and ballast required for the intended application. However, a particular fixture can 

often hold more than one type of lamp and ballast combination. For example, a high bay fixture 

for maintenance or storage areas may operate with an HPS lamp and ballast as well as a MH 

lamp and ballast. 

If an HID lamp must be retrofitted in an existing fixture, it is important to ensure that the 

lamp wattage matches that of the ballast. A higher wattage lamp on a lower wattage ballast 

causes the lamp to operate at a lower efficacy, and the life of the lamp may decrease. Further, the 

starting and operating voltages of the retrofit lamp must match that of the lamp being replaced. 

For example, HPS lamps that require a high-voltage pulse to start may not operate on probe-start 

MV or MH ballasts that start lamps with lower voltage requirements. Certain MH lamps that 

have an operating voltage close to that of MV lamps may work in a MV fixture. 

Finally, while it is important to match the electrical characteristics and operating 

requirements of the lamp with those of the ballast, it is also necessary to ensure that the retrofit 

HID lamp matches the fixture constraints and safety requirements. For instance, MV fixtures that 

are not enclosed cannot protect against possible lamp rupture of an installed MH lamp. Such a 

fixture may only use retrofit lamps that are rated for open enclosures. Retrofitting some fixtures 

may also void the Underwriters Laboratories Inc. (UL) safety certification. It is also important to 

ensure that the retrofit lamp does not negatively impact the light distribution of the fixture. Some 

fixtures cannot adjust to small variations in the position of the arc tube within the fixture, thereby 

decreasing the quality of light emitted. Therefore, it is important to ensure that the lamp being 

retrofitted meets all criteria before installing it in an existing fixture. 

3.4.7 HID Lamp Technology Options 

The following sections summarize the technology options that DOE is considering in this 

rulemaking as viable methods of increasing the efficacy of HID lamps. Please see sections 3.4.2

through 3.4.4 for more detailed descriptions of each technology option. 

3.4.7.1 Mercury Vapor 

MV ballasts, other than specialty application MV ballasts, have been banned from import 

or production in the United States since January 1, 2008. (42 U.S.C. 6295 (ee)) This ban 

effectively limits the installation of new MV fixtures and ballasts, meaning the only MV lamps 

currently being sold are replacement lamps. DOE understands that there is limited industry 

design emphasis on MV lamps, that there are limited methods to improving the efficacy of MV 

lamps, and that the common pathway increase efficacy is a change of technology to MH or HPS 

lamps. 

 

y

 In some cases, the ballast may be installed external to the fixture. For example, the ballast can be installed inside 

the pole in lighting applications that use pole-mounted fixtures. 
3-53

3.4.7.2 High-Pressure Sodium 

HPS lamps are very efficacious (up to 150 lm/W), but have intrinsically poor color 

quality. DOE is aware of only one current option that could achieve higher efficacy in HPS 

lamps:

Sapphire Arc Tubes. The arc tube assembly contains the gases that are excited to 

generate light. The arc tubes in current commercially available HPS lamps are constructed of a 

ceramic material known as polycrystalline alumina (PCA). Through its own research, DOE 

found academic papers that indicated potential increases in efficacy were possible by 

constructing the arc tubes out of a sapphire material, or single crystal aluminum oxide. Sapphire 

has improved light transmission characteristics that would allow for a moderate improvement in 

efficacy. However, the sapphire material introduces unique design difficulties because of its 

tendency to expand differently along each of its three axes. When sapphire is formed into an arc 

tube, this asymmetry in material expansion may result in rupture of the arc tube. Through 

research and manufacturer feedback, DOE estimates that HPS lamp efficacy could increase by 

five percent when changing from PCA to sapphire arc tubes. 

Several manufacturers produced an HPS lamp with a sapphire arc tube, the first 

appearing in the late 1970s. Manufacturers have since discontinued production of these lamps, 

though DOE does not have information on the specific causes of the discontinuance. At this 

time, lamps using sapphire arc tube technology are not available commercially or in a working 

prototype. 

3.4.7.3 Metal Halide 

DOE is aware of several technology options that can improve MH lamp efficacy. DOE 

intends to evaluate the following technology options: 

Arc Tube Design. Potential improvement options include changing the material of the arc 

tube from quartz to ceramic and changing the size and shape of the arc tube. Some of these 

options, however, may not be compatible with all MH systems. For example, ceramic arc tubes 

are used only with low-frequency (typically 200-400 Hz) pulse-start MH systems. 

o Ceramic Arc Tubes. Manufacturers have introduced commercial pulse-start ceramic 

metal halide (CMH) lamps with higher efficacy and better color characteristics than 

quartz pulse-start MH lamps. 

o Arc Tube Shape. The shape of the arc tube relates to the efficacy of the lamp. Certain arc 

tube shapes (like formed or offset electrode) can be more efficacious than others for 

horizontal operating orientations. These arc tube shapes help position the lamp arc in a 

way that increases MH vapor pressure, leading to increased light output. For example, 

formed body arc tubes follow the contours of the arc, ensuring a more uniform thermal 

profile, and minimize heat loss through the smaller pinch seals than pinched body arc 

tubes. 
3-54

Starting Method. Pulse-start lamps are often more efficacious than probe-start lamps. 

The removal of the probe electrode needed in probe-start lamps can allow for more efficacious 

arc tube designs by providing more flexibility for shaping the ends of the arc tube. Some arc tube 

shapes can lead to a slightly higher initial efficacy than others. 

3.5 EQUIPMENT CLASSES

In general, when evaluating and establishing energy conservation standards, DOE divides 

covered equipment into classes by: (a) the type of energy used; and (b) capacity of the product or 

(c) any other performance-related feature that justifies different standard levels, such as features 

affecting consumer utility. (42 U.S.C. 6295(q)) DOE then conducts its analysis and considers 

standards for each equipment class. 

DOE considered several possible characteristics or features of HID lamps that could 

warrant separation of covered equipment into different equipment classes, including: 

 correlated color temperature (CCT), 

 wattage, 

 bulb finish,

 luminaire characteristic, 

 bulb shape, 

 base type, and 

 lamp operating orientation. 

As detailed in chapter 2 of the interim TSD, DOE is considering exempting directional HID 

lamps and self-ballasted HID lamps from the scope of this rulemaking and is therefore not 

considering directionality or ballast location as class-setting factors in the interim analysis. The 

remaining class-setting factors are discussed below. 

3.5.1 Correlated Color Temperature 

In general terms, CCT represents the color appearance of a light source and is expressed 

in Kelvins (K). The higher the CCT, the cooler or more blue the light appears, and the lower the 

CCT, the warmer or more red the light appears. HID lamps are available with a wide range of 

CCT values depending on lamp type and design. DOE’s analysis of commercially available lamp 

catalog data concluded that CCT is correlated with lamp efficacy. DOE determined that higherCCT lamps were less efficacious than lower CCT lamps of the same wattage. 

DOE identified distinct differences in efficacies for lamps with CCT values 1900 K and 

2800 K; 2800 K and 4500 K; and 4500 K and 7000 K. For example, a 250 W lamp with a 

CCT 1900 K and 2800 K has a maximum efficacy of about 116 lm/W, a 250 W lamp with a 

CCT 2800 K and 4500 K has a maximum efficacy of about 100 lm/W, and a 250 W lamp with 

a CCT >4500 K and <7000 K has a maximum efficacy of about 76 lm/W. 

Because CCT is an approximation of the color appearance of the color of a lamp, 

customers typically specify different CCTs for different applications. For example, in indoor 

applications, customers typically specify a CCT of 3000 K to 4500 K, based on the preferences 
3-55

of their occupants. Because of these preferences and behavior, DOE believes that CCT offers 

customers unique utility. 

Because CCT affects HID lamp efficacy and impacts utility, DOE has preliminarily 

decided to establish separate equipment classes based on CCT. These equipment class divisions 

are summarized below in Table 3.5.1. 

Table 3.5.1 Equipment Class Divisions Based on CCT 

CCT Range

≥1900 K and ≤2800 K

2800 K and ≤4500 K

4500 K and <7000 K

3.5.2 Wattage 

HID lamps are available with a variety of light outputs, or lumen outputs, and input 

powers, or wattages. Light output and input power are highly correlated (increased input power 

typically leads to increased light output). DOE’s initial review of manufacturer catalogs for the 

framework document determined that HID lamps with increased light outputs (and therefore 

increased input powers) were generally more efficacious than lamps with lower light outputs 

(and therefore lower input powers). Because customers typically require specific light output 

from a lamp depending on the intended use for the lamp, in the framework document DOE 

considered establishing separate equipment classes based on light output. 

DOE notes that the use of light output as a class-setting factor could result in HID lamps 

of the same wattage being placed in separate equipment classes and therefore subject to different 

standards. DOE received feedback that customers typically choose lamps in terms of wattage, in 

part because it serves the dual role of identifying which ballasts can be paired with the lamp. As 

a result, and for the additional reasons discussed below, DOE considered establishing separate 

equipment classes based on wattage. 

As discussed in chapter 2 of the interim TSD, DOE is considering covering only HID 

lamps with rated wattages 50 W and 1000 W for HPS and MV lamps and 50 W and 2000 

W for MH lamps. Because of the typical CCT values of the HID lamp types, DOE determined 

that these wattage delineations correlated with a maximum wattage of 1000 W for lamps in the 

lower CCT range and a maximum wattage of 2000 W for lamps in the middle and highest CCT 

ranges. 

When examining manufacturer catalog data, all other features remaining constant, DOE 

observed that HID lamp efficacy generally increases with increasing lamp wattage. This 

correlation is because there are certain fixed losses within a lamp associated with current passing 

through the electrodes (known as end losses) and with thermal losses from the arc to the arc tube 

wall. When the wattage increases, the fixed losses are a smaller portion of the overall losses, thus 

making the lamp more efficacious. 

In addition to affecting efficacy, DOE believes that lamp wattage impacts consumer 

utility. Typically, a lamp with a higher wattage will provide more light. Because customers 

require varying light levels depending on the application and location of the lamp, lamp wattage 
3-56

provides utility to the customer. Further, ballasts are typically designed to operate specific lamp 

wattages, indicating that a change in lamp wattage often requires a change in ballast. In the 

interim analysis, therefore, DOE has decided to consider wattage as a potential class-setting 

factor rather than lumen output. However, DOE continues to use lumen output as a factor when 

selecting higher-efficacy lamp replacements. 

Because DOE decided to use equations to relate efficacy and wattage, the efficacy levels 

considered in this interim analysis account for the observed trend of increasing efficacy with 

increasing lamp wattage. The reasoning and methodology for this decision is further explained in 

chapter 5. However, even when using an equation to relate efficacy and wattage, DOE observed 

that the same design options were not available at all wattages. For example, CMH lamps were 

only available at 400 W and below, pulse-start quartz MH lamps were only available at 1000 W 

and below, and only probe-start quartz MH lamps were available through 2000 W. Therefore, 

DOE subdivided the higher two CCT ranges based on lamp wattage. In these two CCT ranges, 

DOE created separate equipment class divisions for the following wattage ranges: (1) 50 W and 

400 W; (2) 400 W and 1000 W; and (3) 1000 W and 2000 W. For the lowest CCT range, 

wattage divisions were not necessary because the same number of energy saving alternatives 

were available at all of the wattages. These equipment class divisions are summarized in Table 

3.5.2.

Table 3.5.2 Equipment Class Divisions Based on Wattage 

CCT Range Wattage

1900 K and ≤2800 K 50 W and ≤1000 W

2800 K and ≤4500 K

50 W and ≤400 W

400 W and ≤1000 W

1000 W and ≤2000 W

4500 K and <7000 K

50 W and ≤400 W

400 W and ≤1000 W

1000 W and ≤2000 W

3.5.3 Bulb Finish 

In reviewing catalogs, DOE observed that HID lamps are offered with several different 

bulb finishes, such as clear, coated, diffuse, frosted, white, or deluxe white. Some of these labels 

apply to only certain types of HID lamps. For example, in addition to being classified as coated, 

DOE has found HPS lamps labeled as diffuse lamps, MH lamps labeled as frosted, and MV 

lamps labeled as white or deluxe white lamps. DOE determined that the difference among all of 

these terms was generally based on marketing techniques. However, across all manufacturers, 

DOE notes that most coated lamps have phosphor coatings applied to the inner wall of the outer 

bulb, whereas clear lamps do not have this coating. For this rulemaking, DOE defines “coated 

lamps” as all lamps that are not clear because the terms coated, diffuse, frosted, white, or deluxe 

white typically represent the same or nearly the same bulb finish within a lamp type. 

The coating on a lamp blocks a portion of the light produced by the arc tube from leaving 

the lamp. Thus, coated lamps should have lower efficacies than their clear counterparts. By 

comparing pairs of coated and clear lamps, all other features remaining the same or similar, DOE 

found that a coating on MH and HPS lamps reduced overall lamp efficacy. However, for MV 
3-57

lamps, DOE determined that coated lamps were more efficacious than their clear counterparts. 

Based on manufacturer feedback during interviews, this relationship exists because MV lamps 

generate a large amount of ultraviolet (UV) light and the coating on MV lamps converts the UV 

light into visible light, thereby increasing the efficacy of the lamp. 

DOE believes that for all three types of HID lamps, a coated lamp offers unique utility 

For MH and HPS lamps, a coating is often applied to reduce the glare perceived by the customer. 

For MV lamps, a coating often impacts the CCT and efficacy of the lamp. As discussed above, 

DOE believes that CCT offers unique consumer utility. 

Given the impact on efficacy and utility, DOE established separate equipment classes for 

clear and coated MH and HPS lamps in their respective wattage and CCT ranges. For MV lamps, 

DOE determined that an equipment class division was not necessary because the CCT equipment 

class divisions already separate coated MV lamps from clear MV lamps. DOE found all clear 

MV lamps in the scope of this rulemaking have a CCT 4500 K and 7000 K, while all coated 

MV lamps in the scope are 2800 K and 4500 K. Because clear MH lamps are the most likely 

replacements for coated MV lamps in the applicable CCT ranges, DOE has preliminarily 

determined that MV lamps should be categorized in the clear bulb finish equipment classes 

(regardless of the bulb finish of the MV lamp itself). These equipment class divisions are 

summarized in Table 3.5.3.

Table 3.5.3 Equipment Class Divisions Based on Bulb Finish 

CCT Range Wattage Bulb Finish*

1900 K and ≤2800 K 50 W and ≤ 1000 W Clear

Coated

2800 K and ≤4500 K

50 W and ≤ 400 W Clear

Coated

400 W and ≤ 1000 W Clear

Coated

1000 W and ≤ 2000 W Clear

Coated

4500 K and <7000 K

50 W and ≤ 400 W Clear

Coated

400 W and ≤ 1000 W Clear

Coated

1000 W and ≤ 2000 W Clear

Coated

* MV lamps, regardless of bulb finish, are placed in the clear equipment class for their 

respective CCT and wattage.

3.5.4 Luminaire Characteristic 

MH lamps are frequently listed with a luminaire characteristic, typically open-rated or 

enclosed-rated, to indicate in which type of fixture the lamps should be used. An open fixture 

does not have a physical barrier that separates the lamp from the space that is to be illuminated. 

Open-rated lamps have a glass shroud that surrounds the arc tube to protect the environment and 
3-58

any occupants around the lamp in the event of arc tube rupture.z An enclosed fixture does have a 

physical barrier that separates the lamp from the space that is to be illuminated. Enclosed-rated 

lamps do not have the glass shroud surrounding the arc tube and must be used in enclosed 

fixtures to satisfy safety requirements.aa DOE also found commercially available lamps that were 

labeled as S-rated.bb S-rated lamps do not have a glass shroud around the arc tube, but can be 

used in open-rated fixtures under certain defined conditions. Because S-rated lamps do not 

feature a shroud, DOE determined their efficacy potential would be comparable to traditional 

enclosed-rated lamps. 

DOE notes that luminaire characteristic applies only to MH lamps. This is because MH 

lamps typically operate at temperatures and pressures significantly higher than that of HPS or 

MV lamps. By comparing pairs of open-rated and enclosed-rated MH lamps with all other lamp 

characteristics and features remaining the same or similar, DOE determined that enclosed-rated 

MH lamps are more efficacious than their open-rated counterparts. DOE attributes the efficacy 

gain to the removal of the shroud that covers the entire arc tube and blocks a small percentage of 

light from leaving the lamp. Because the shroud is a safety feature that is required for open 

fixtures, DOE believes open-rated lamps offer unique utility. 

Given the impact on both consumer utility and lamp efficacy, DOE established separate 

equipment classes for enclosed-rated versus open-rated lamps. For this interim analysis, DOE 

placed HPS and MV lamps in the enclosed-rated equipment classes because they do not have a 

protective glass covering. HPS and MV lamps would be subject to the same energy conservation 

standards as enclosed-rated lamps, even though DOE recognizes these lamps could be used in 

open fixtures in practice. These equipment class divisions are summarized in Table 3.5.4. 

 

z

 DOE proposes to adopt the ANSI C78.380-2007 definition of open-rated: “Lamp may be used in an open 

luminaire. The effective antic UV output of the lamp shall not exceed 2 mW/klm for a non-reflector lamp or 2 

mW/(m2∙klx) for a reflector lamp. Metal halide Type O lamps must meet specified containment test requirements.” 

aa DOE proposes to adopt the ANSI C78.380-2007 definition of enclosed-rated: “Lamp may be used in an enclosed 

luminaire that meets industry standards for containment in the event of lamp rupture. The effective antic UV output 

of the lamp shall not exceed 2 mW/klm for a non-reflector lamp or 2 mW/(m2∙klx) for a reflector lamp.” 

bb ANSI C78.380-2007 defines S-rated lamps as: “Lamp may be used in an open luminaire if position restrictions are 

followed. Otherwise, the lamp requires an enclosed luminaire that meets industry standards for containment in the 

event of lamp rupture. Specific containment test requirements do not apply to this type of lamp. The effective actinic 

UV output of the lamp shall not exceed 2 mW/klm for a non-reflector lamp or 2 mW/(m2∙klx) for a reflector lamp. 

This letter is not to be used for luminaire designation on lamps other than metal halide.” 
3-59

Table 3.5.4 Equipment Class Divisions Based on Luminaire Characteristic 

CCT Range Wattage Bulb 

Finish*

Luminaire 

Characteristic**

1900 K and ≤2800 K 50 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

2800 K and ≤4500 K

50 W and ≤400 W

Clear Enclosed

Open

Coated Enclosed

Open

400 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

1000 W and ≤2000 W

Clear Enclosed

Open

Coated Enclosed

Open

4500 K and <7000 K

50 W and ≤400 W

Clear Enclosed

Open

Coated Enclosed

Open

400 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

1000 W and ≤2000 W

Clear Enclosed

Open

Coated Enclosed

Open

* MV lamps regardless of bulb finish are placed in the clear equipment classes for their 

respective CCT and wattage.

** MV and HPS lamps are placed in the enclosed equipment classes for their respective wattage 

and CCT.

3.5.5 Bulb Shape 

The bulb shape reflects the overall size and shape of a lamp. Bulb shapes are indicated by 

combinations of letters while lamp diameters are indicated by numeric values, in eighths of an 

inch. For example, a BT37 lamp is a blown tubular lamp with a diameter of 37 eighths of an 

inch, or 4.625 inches. Common HID lamp shapes are BD (blown dimpled), BT (blown tubular), 

ED (elliptical dimpled), ET (elliptical tubular), and T (tubular). The bulb is meant to contain and 

protect the main light-producing portion of the lamp, i.e., the arc tube and electrodes. 

By comparing pairs of lamps in which bulb shape was the only characteristic that 

differed, DOE did not find any direct impact on efficacy associated with a change in bulb shape 

(e.g., from ED17 to BT17) or bulb size (e.g., from ED17 to ED28) or the combination of the two. 

For that reason, DOE does not consider bulb shape to be a class-setting factor in this rulemaking. 
3-60

Although DOE is not separating equipment classes based on bulb shape, DOE recognizes 

that the bulb shape (or any other physical dimensions) is important when determining higherefficacy lamp replacements. Higher-efficacy replacements are discussed in chapter 5 of the 

interim TSD. 

3.5.6 Base Type 

HID lamps have different base types depending on the fixture and socket with which the 

lamp are designed to operate. The most common base type is a screw base, which includes both 

medium screw bases (E26) and mogul screw bases (E39 for enclosed fixtures, EX39 for open 

fixtures, and EP39 for orientation-specific lamps). Mogul screw bases are typically used at 

higher wattages, whereas medium screw bases are typically used at lower wattages. 

By comparing pairs of lamps in which base type was the only characteristic that differed, 

DOE’s analysis indicated that base type does not impact the efficacy of HID lamps. Therefore, 

DOE does not consider base type to be a class-setting factor in this rulemaking. 

However, similar to bulb shape, DOE recognizes the importance of base type in selecting higherefficacy lamp replacements and considers base type in the engineering analysis, discussed in 

chapter 5 of the interim TSD. 

3.5.7 Lamp Operating Orientation 

Catalogs indicate whether an HID lamp is designed to operate at either a specific 

orientation or at several orientations. In DOE’s review of commercially available catalog data, 

DOE identified several operating orientations, including the universal, horizontal, and vertical 

orientations, as well as the degrees of operating tolerance associated with those orientations. 

DOE believes that there are distinct differences in utility for operating orientations 

because applications served by certain luminaires can frequently only operate a lamp in a 

specific orientation. For example, street and area luminaires typically position the lamp in a 

horizontal orientation, while indoor high-bay luminaires typically use a vertical (base-up) 

orientation. Some lamps are designed specific to the horizontal or vertical operating orientations, 

but some lamps are designed to operate in any orientation. These lamps have the advantage of 

inventory reduction (because one lamp can serve all orientations) and ease of installation (lamps 

cannot be installed in the wrong orientation, which would result in reduced performance). 

Manufacturers frequently provide performance data for a universal lamp operated in both 

the vertical and horizontal orientations. In theory, because universal lamps cannot be optimized 

specifically to the vertical or horizontal orientation, they would have a reduced maximum 

efficacy relative to a position specific lamp. However, DOE analyzed the efficacy of universal 

lamps operated in the vertical orientation compared with vertical-only lamps and horizontal-only 

lamps and did not find conclusive indication of whether universal lamps were more or less 

efficacious than vertical or horizontal lamps. In addition, DOE found no conclusive evidence of a 

difference in efficacy between vertical-only and horizontal-only lamps. 
3-61

Without conclusive evidence of lamp operating orientation impacting efficacy, DOE does 

not consider operating orientation to be a class-setting factor in this rulemaking. However, DOE 

recognizes that the operating orientation is important when determining higher-efficacy lamp 

replacements. Higher-efficacy replacements are discussed in chapter 5 of the interim TSD. 

3.5.8 Equipment Class Summary 

The equipment class divisions are summarized in Table 3.5.5. 

Table 3.5.5 HID Lamps Interim Analysis Equipment Classes 

CCT Range Wattage Bulb 

Finish*

Luminaire 

Characteristic**

1900 K and ≤2800 K 50 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

2800 K and ≤4500 K

50 W and ≤400 W

Clear Enclosed

Open

Coated Enclosed

Open

400 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

1000 W and ≤2000 W

Clear Enclosed

Open

Coated Enclosed

Open

4500 K and <7000 K

50 W and ≤400 W

Clear Enclosed

Open

Coated Enclosed

Open

400 W and ≤1000 W

Clear Enclosed

Open

Coated Enclosed

Open

1000 W and ≤2000 W

Clear Enclosed

Open

Coated Enclosed

Open

* MV lamps regardless of bulb finish are placed in the clear equipment classes for their 

respective CCT and wattage.

** MV and HPS lamps are placed in the enclosed equipment classes for their respective wattage 

and CCT.
3-62

REFERENCES 

1 Ron Runkles. The NEMA Lighting Systems Division. 2010. (Last accessed February 15, 2013). 

<http://www.nema.org/Products/Documents/lightingsystemsdivision.pdf >.

2 U.S. Small Business Administration. Table of Small Business Size Standards Matched to North 

American Industry Classification System Codes. October 2012. (Last accessed February 15, 

2013). <http://www.sba.gov/sites/default/files/files/Size_Standards_Table.pdf >.

3 California Energy Commission. 2010 Appliance Efficiency Regulations. 2010. (Last accessed 

February 15, 2013). <http://www.energy.ca.gov/2010publications/CEC-400-2010-012/CEC-400-

2010-012.PDF>. 

4 Natural Resources Canada, Office of Energy Efficiency. Canada’s Energy Efficiency 

Regulations. 2011. (Last accessed February 15, 2013). 

<http://oee.nrcan.gc.ca/regulations/11239>.

5

European Commission. Commission Regulation (EC) No 245/2009. March 18, 2009. (Last 

accessed February 15, 2013). <http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:076:0017:0044:EN:PDF>. 

6

European Commission. Commission Regulation (EU) No 347/2010. April 21, 2010. (Last 

accessed February 15, 2013). <http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:104:0020:0028:EN:PDF>. 

7 U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Federal 

Energy Management Program. Covered Product Category: Industrial Luminaires. 2011. (Last 

accessed February 15, 2013). 

<http://www1.eere.energy.gov/femp/technologies/eep_hid_lumen.html> 

8 U.S. Environmental Protection Agency and U.S. Department of Energy. About ENERGY 

STAR. (Last accessed February 15, 2013). 

<http://www.energystar.gov/index.cfm?c=about.ab_index>. 

9 U.S. Environmental Protection Agency and U.S. Department of Energy. Residential Light 

Fixtures Key Product Criteria. (Last accessed February 15, 2013). 

<http://www.energystar.gov/index.cfm?c=fixtures.pr_crit_light_fixtures>. 

10 U.S. Environmental Protection Agency and U.S. Department of Energy. ENERGY STAR 

Program Requirements for Luminaires. (Last accessed February 15, 2013). 

<http://www.energystar.gov/ia/partners/prod_development/new_specs/downloads/luminaires/Fin

al_Luminaires_Program_Requirements.pdf?2162-eba4>.

11 U.S. Environmental Protection Agency and U.S. Department of Energy. ENERGY STAR 

Lamps Draft 3 Version 1.0 Specification. 2012. (Last accessed February 15, 2013) < 

https://www.energystar.gov/products/specs/node/273 > 
3-63

12 Efficiency Vermont. SMARTLIGHT Discounted Replacement Lamp Program. 2013. (Last 

accessed February 15, 2013). <http://www.efficiencyvermont.com/for_my_business/ways-tosave-and-rebates/commercial_lighting/metal_halide/MetalHalideRebates/smartlight.aspx>.

13 Pacific Gas and Electric. 2013-2014 Business Rebate List. 2013. (Last accessed February 15, 

2013). < 

http://www.pge.com/includes/docs/pdfs/mybusiness/energysavingsrebates/incentivesbyindustry/

Business_Rebates_List.pdf >.

14 Pacific Gas and Electric. Lighting Rebate Catalog. January 2013. (Last accessed February 15, 

2013). 

<http://www.pge.com/includes/docs/pdfs/mybusiness/energysavingsrebates/incentivesbyindustry

/lighting_catalog_final.pdf>.

15 San Diego Gas and Electric. Energy Efficiency Business Incentives. 2013. (Last accessed 

February 15, 2013). < 

http://www.sdge.com/sites/default/files/documents/135293665/Business%20Incentives%20Fact

%20Sheet.pdf?nid=1286>.

16 San Diego Gas and Electric. Energy Efficiency Business Rebates Product Catalog. 2013. (Last 

access February 15, 2013). < 

http://www.sdge.com/sites/default/files/documents/1232647385/Lighting%20Product%20Catalo

g.pdf?nid=4006>.

17 Omaha Public Power District. 2013 Lighting Incentive Program. 2013. (Last accessed 

February 15, 2013). < 

http://www.oppd.com/prodconsump10g/groups/web/documents/webcontent/22_007476.pdf > 

18 Omaha Public Power District. 2013 Lighting Configurations Reference Sheet. 2013. (Last 

accessed February 15, 2013). < 

http://www.oppd.com/prodconsump10g/groups/web/documents/webcontent/22_006801.pdf >.

19 Lyon-Lincoln Electric Cooperative, Inc. Commercial & Ag Rebates. 2013. (Last accessed 

February 15, 2013). <http://llec.coop/content/commercial-ag-lighting>. 

20 Lyon-Lincoln Electric Cooperative, Inc. Lighting Retrofit Rebate. 2013. (Last accessed 

February 15, 2013). 

<http://www.llec.coopwebbuilder.com/sites/llec.coopwebbuilder.com/files/lighting_rebate_form

s_-_retrofit.pdf> 

21 ElectriCities of North Carolina, Inc. NCMPA1 Energy Efficiency Programs. 2012. (Last 

accessed February 15, 2013). < http://www.ncpublicpower.com/SaveEnergy/NCMPA1.aspx >.
3-64

22 U.S. Census Bureau. Manufacturing, Mining, and Construction Statistics. Current Industrial 

Reports, Electric Lighting Fixtures, MA335L. 2001. (Last accessed February 15, 2013). 

<http://www.census.gov/mcd/> 

23 The M.I.T. Press. 1971. Electric Discharge Lamps. J. F. Waymouth. 

24 Illuminating Engineering Society of North America. 2000. The IESNA Lighting Handbook: 

Reference and Application. 9th Edition. M.S. Rea. New York. 2000.

25 Zukauskas, A., Shur, M. S., Gaska, R. Introduction to Solid-State Lighting. 2002. John Wiley 

& Sons, Inc.: New York, NY. 

26 Pacific Gas and Electric Company. High Pressure Sodium Lamps A Pacific Energy Center 

Factsheet. (Last accessed February 15, 2013). 

<http://www.lightingassociates.org/i/u/2127806/f/tech_sheets/High_Pressure_Sodium_Lamps.pd

f>. 

27 Westinghouse Research and Development Center. Physics and Chemistry of High Pressure 

Sodium Lamps. R. J. Zollweg. March 8, 1982. 

28 OSRAM SYLVANIA. Lumalux/Unalux High Pressure Sodium Lamps. Engineering Bulletin 

HID009. (Last accessed February 15, 2013). 

<http://www1.eere.energy.gov/buildings/appliance_standards/commercial/pdfs/hid_lamps/sylvan

ia_2003b.pdf>. 

29 Philips Advance. Pocket Guide to High Intensity Discharge Lamp Ballasts. 2009. Rosemont, 

IL. (Last accessed February 15, 2013). < http://rexelusa.electriccatalogs.com/DocumentViewer.aspx?fileName=Philips%20Advance%20HID%20Pocket%20Gu

ide%202009.pdf>. 

30 Edison Tech Center. The Sodium Lamp. M. Whelan and R. DeLair. (Last accessed February 

15, 2013). <http://edisontechcenter.org/SodiumLamps.html>.

31 Simpson, R. S. Lighting Control: Technology and Applications. 2003. Focal Press: Oxford, 

UK.

32 Journal of the Illuminating Engineering Society. A Noncycling High Pressure Sodium Lamp.

P. Ingalls, R. Dolan, J. Plumb, H. Zhu, and E. Wyner. Summer 1995: pp. 19 – 25. 

33 Illuminating Engineering Society of North America. 2011. The IESNA Lighting Handbook 

Tenth Edition: Reference and Application. 10th Edition. D. DiLaura, K. Houser, R. Mistrick, and 

G. Steffy. 

34 U.S. Department of Energy—Office of Energy Efficiency and Renewable Energy. Energy 

Conservation Program for Consumer Products: Technical Support Document: Energy Efficiency 

Standards for Consumer Products: High-Intensity Discharge Lamps Analysis of Potential Energy 
3-65

Savings. December 2004. Washington, D.C. (Last accessed February 15, 2013). 

<http://www.eere.energy.gov/buildings/appliance_standards/commercial/pdfs/hid_energy_savin

gs_report.pdf>.

35 Philips Lighting. Energy Saving Ceramic Metal Halide Lamps suitable for Probe-Start and 

Pulse-Start Systems. T. Steere, R. Gibson, and J. Tu. 

36 Journal of the Illuminating Engineering Society. Metal Halide Lamps With Ceramic 

Envelopes: A Breakthrough in Color Control. S. Carleton, P.A. Seinen, and J. Stoffels. Winter 

1997: pp. 139–145.

37 BLI Lighting Specialists. Shedding Light on Arc-Tube Rupture.(Last accessed February 15, 

2013). <http://www.budgetlighting.com/shat-r-shield/pdfs/arctube.pdf> 

38 U.S. Department of Energy. Metal Halide – Advances & Improvements. D. Houghton. (Last 

accessed February 15, 2013). 

<http://www1.eere.energy.gov/buildings/appliance_standards/commercial/pdfs/hid_lamps/hough

ton_2002.pdf> 

39 National Electrical Manufacturers Association. Best Practices for Metal Halide Lighting 

Systems, Plus Questions and Answers about Lamp Ruptures in Metal Halide Lighting Systems. 

(Last accessed February 15, 2013). 

<http://www.geappliances.com/email/lighting/specifier/2008_07/downloads/NEMABestPractice

s.pdf> 

40 Ribarich, T. A Systems Approach to Ballast IC Design. 1999. Philips Semiconductor, Power 

Semiconductor Applications: El Segundo, CA.